This document discusses the selection of spring materials using the PROMETHEE method. It begins with an introduction to springs, their history, common materials used, and the importance of selecting the right material. It then discusses previous literature on spring material testing and optimization. The document considers seven spring material alternatives that are evaluated based on eight selection criteria using the PROMETHEE II and GAIA techniques. Chrome silicon alloy steel is found to be the best material, followed by high carbon steel and Inconel 600, with Monel K500 as the worst choice.
This document analyzes the stress on helical coil springs made of different materials that are used in two-wheeler vehicles. It discusses the modeling of a spring in CATIA software and analyzing it in ANSYS. Four materials are considered - structural steel, aluminum alloy, titanium alloy, and chrome vanadium. The maximum shear stress and total deformation of each material under load are calculated and chrome vanadium is found to have the lowest stress and deformation, making it the best material out of the four considered for springs.
IRJET- Comparative Study on Behaviour of Cold-Formed Purlin Section-Review PaperIRJET Journal
This document presents a review of literature on the comparative study of the behavior of cold-formed steel purlin sections. It first introduces that cold-formed steel members are formed at room temperature and have higher yield strength than hot-rolled members. The literature review then summarizes several papers that have analyzed the load carrying capacity and deflection of various cold-formed sections through analytical and finite element models. These studies compared the behavior of cold-formed sections to hot-rolled sections. The conclusion is that cold-formed steel is increasingly being used in structures due to its properties and that further research is needed to study the behavior of built-up cold-formed sections.
IRJET- Comparative Study on Behaviour of Cold-Formed Purlin Section-Revie...IRJET Journal
This document presents a review of literature on the comparative study of the behavior of cold-formed steel purlin sections. It summarizes several studies that have analyzed the load carrying capacity and deflection of various cold-formed and hot-formed steel sections under elastic parameters through analytical and finite element methods. The literature reviewed includes studies on the bending and twisting behavior of channel-section purlins, buckling behavior of laterally-restrained Z-section beams, interaction of local and distortional buckling modes in lipped channel beams, and torsional behavior of cold-formed steel sections. The conclusions drawn are that cold-formed steel is increasingly being used in structures due to its inherent properties and thinner gauge compared to hot
The document summarizes the manufacturing process for coil springs. It describes the key steps which include coiling the wire using either cold or hot winding techniques, heat treating to relieve stress, grinding and finishing the ends, shot peening to strengthen the spring, setting the coils, coating for corrosion protection, packaging, and quality control testing. Computer-controlled coiling machines help improve quality by precisely controlling the spring dimensions and adjusting in real-time.
This document discusses the effect of using alternative shapes for main reinforcement in concrete slabs. Specifically, it examines using rectangular trough, trapezoidal trough, or V-shaped reinforcement rather than the typical horizontal reinforcement. Using alternative shapes could increase the moment-carrying and shear-carrying capacity of slabs while reducing deflection. This is due to the slab acting as a folded plate up to a certain limit because of the reinforcement shape. The document also discusses using this concept with ferrocement slabs to further increase strength with reduced dead load. In conclusion, reinforcement shape affects structural behavior and alternative shapes may provide design and structural benefits over conventional horizontal reinforcement.
The Study of Premature Failure of Springs Used In Railway CoachesIOSR Journals
The document discusses the premature failure of springs used in Indian railway coaches. It provides background on the Indian railway system and the types of springs used in coach suspensions. Finite element analysis is performed on models of closed-end and open-end helical compression springs used in coaches to understand stresses and failure points. The analysis finds von Mises stresses higher than the yield strength of the spring material, indicating failure under the given loads and boundary conditions for both spring types. Resonant frequencies are also identified that could lead to higher amplitudes and failure under dynamic operating conditions. The study aims to help improve spring design and service life for Indian railways.
Steel Reinforcement Facts Every Civil Engineer Must KnowSHAZEBALIKHAN1
Steel is the core building material and finds numerous uses in construction.
Learn about the 6 facts about steel reinforcement. Why do we use steel reinforcement? Types of steel reinforcement. Grade of steel. Positive and negative reinforcement. The cover requirement of steel. And nominal steel requirement of structures.
Finite Element Modeling for Effect of Fire on Steel Structure: A ReviewIJERA Editor
Fire performance of structural steel at elevated temperature includes the study of steel frame subjected to fire.
Also the effect of stress strain temperature on the fire performance of structural steel should be observed. The
behavior of a steel frame in a fire depends on many factors including the properties of the steel and the coating
material on it. The present paper shows reviews of various research works carried out by several researchers on
the effects of stress–strain relationships on the fire performance of steel frame exposed to uniformly increasing
temperature when steel is unprotected and protected with concrete using FEM.
This document analyzes the stress on helical coil springs made of different materials that are used in two-wheeler vehicles. It discusses the modeling of a spring in CATIA software and analyzing it in ANSYS. Four materials are considered - structural steel, aluminum alloy, titanium alloy, and chrome vanadium. The maximum shear stress and total deformation of each material under load are calculated and chrome vanadium is found to have the lowest stress and deformation, making it the best material out of the four considered for springs.
IRJET- Comparative Study on Behaviour of Cold-Formed Purlin Section-Review PaperIRJET Journal
This document presents a review of literature on the comparative study of the behavior of cold-formed steel purlin sections. It first introduces that cold-formed steel members are formed at room temperature and have higher yield strength than hot-rolled members. The literature review then summarizes several papers that have analyzed the load carrying capacity and deflection of various cold-formed sections through analytical and finite element models. These studies compared the behavior of cold-formed sections to hot-rolled sections. The conclusion is that cold-formed steel is increasingly being used in structures due to its properties and that further research is needed to study the behavior of built-up cold-formed sections.
IRJET- Comparative Study on Behaviour of Cold-Formed Purlin Section-Revie...IRJET Journal
This document presents a review of literature on the comparative study of the behavior of cold-formed steel purlin sections. It summarizes several studies that have analyzed the load carrying capacity and deflection of various cold-formed and hot-formed steel sections under elastic parameters through analytical and finite element methods. The literature reviewed includes studies on the bending and twisting behavior of channel-section purlins, buckling behavior of laterally-restrained Z-section beams, interaction of local and distortional buckling modes in lipped channel beams, and torsional behavior of cold-formed steel sections. The conclusions drawn are that cold-formed steel is increasingly being used in structures due to its inherent properties and thinner gauge compared to hot
The document summarizes the manufacturing process for coil springs. It describes the key steps which include coiling the wire using either cold or hot winding techniques, heat treating to relieve stress, grinding and finishing the ends, shot peening to strengthen the spring, setting the coils, coating for corrosion protection, packaging, and quality control testing. Computer-controlled coiling machines help improve quality by precisely controlling the spring dimensions and adjusting in real-time.
This document discusses the effect of using alternative shapes for main reinforcement in concrete slabs. Specifically, it examines using rectangular trough, trapezoidal trough, or V-shaped reinforcement rather than the typical horizontal reinforcement. Using alternative shapes could increase the moment-carrying and shear-carrying capacity of slabs while reducing deflection. This is due to the slab acting as a folded plate up to a certain limit because of the reinforcement shape. The document also discusses using this concept with ferrocement slabs to further increase strength with reduced dead load. In conclusion, reinforcement shape affects structural behavior and alternative shapes may provide design and structural benefits over conventional horizontal reinforcement.
The Study of Premature Failure of Springs Used In Railway CoachesIOSR Journals
The document discusses the premature failure of springs used in Indian railway coaches. It provides background on the Indian railway system and the types of springs used in coach suspensions. Finite element analysis is performed on models of closed-end and open-end helical compression springs used in coaches to understand stresses and failure points. The analysis finds von Mises stresses higher than the yield strength of the spring material, indicating failure under the given loads and boundary conditions for both spring types. Resonant frequencies are also identified that could lead to higher amplitudes and failure under dynamic operating conditions. The study aims to help improve spring design and service life for Indian railways.
Steel Reinforcement Facts Every Civil Engineer Must KnowSHAZEBALIKHAN1
Steel is the core building material and finds numerous uses in construction.
Learn about the 6 facts about steel reinforcement. Why do we use steel reinforcement? Types of steel reinforcement. Grade of steel. Positive and negative reinforcement. The cover requirement of steel. And nominal steel requirement of structures.
Finite Element Modeling for Effect of Fire on Steel Structure: A ReviewIJERA Editor
Fire performance of structural steel at elevated temperature includes the study of steel frame subjected to fire.
Also the effect of stress strain temperature on the fire performance of structural steel should be observed. The
behavior of a steel frame in a fire depends on many factors including the properties of the steel and the coating
material on it. The present paper shows reviews of various research works carried out by several researchers on
the effects of stress–strain relationships on the fire performance of steel frame exposed to uniformly increasing
temperature when steel is unprotected and protected with concrete using FEM.
This document analyzes helical compression springs used in the rear suspension of two-wheeled vehicles. It presents analytical calculations and finite element analysis to determine stresses and deflections in springs made of hard carbon steel and chrome vanadium steel with circular and rectangular cross-sections under various loads. The results show that chrome vanadium steel springs have lower deflections than hard carbon steel springs under the same loads. Chrome vanadium steel is also concluded to be a better replacement material due to its lower cost and ability to work efficiently with less maintenance.
Modification of a Two Wheeler Suspension System using FeaIJERA Editor
A spring is defined as an elastic body, whose function is to compress when loaded and to recover its original
shape when the load is removed. A spring is a flexible element used to exert a force or a torque and, at the same
time, to store energy. The force can be a linear push or pull, or it can be radial. In two wheelers we used to see
helical suspension at the front and rear tyres on both sides. But the new model bikes are replacing the rear
double suspension with the single heavy duty suspension. Our project deals with the design and modification of
the suspension system and analyzing that can we replace one heavy duty spring in the place of double springs.
For this we have conducted structural analysis by varying the spring material and keeping base material same.
By seeing the results, Comparison is done for four materials to validate better material for suspension system by
doing analysis on spring with help of ANSYS software for find out which material is best for the suspension
system.
And also we modified the actual model and also conducting the same analysis on it and validating that which
model is better.
The modeling done in Creo-5 and analysis is done Ansys package.
Analysis and Estimation of Stiffness of Outer Race of Aircraft Bearingspaperpublications3
The document analyzes and estimates the stiffness of the outer race of aircraft bearings. It describes how a bearing outer race was modeled and analyzed in CREO and ANSYS software to determine its deflection and stiffness when subjected to radial loads. The results found a stiffness value of 769.23 kN/mm which was verified through theoretical calculations to be within acceptable limits for aircraft bearing materials.
This technical note investigates the causes of rotor bending in turbines and a thermal straightening method called hot spotting. Hot spotting was performed seven times on a bent rotor using different temperatures and times. The results showed that 690±20°C for 210 seconds provided noticeable straightening without affecting mechanical properties. Finite element modeling also simulated heat distribution under different conditions to determine optimal restraint around the hot spot area.
This document discusses the selection of forging equipment and stock size for open and closed die forging. It begins by classifying forging equipment into work-restricted and stroke-restricted machines such as hammers, presses, and hydraulic presses. It then explains open and closed die forging processes and considerations for die design such as flash, gutter, draft angles, and variation of stroke with load. The document concludes by providing design considerations for blocker, finisher, trim tools, and punches.
Flexural behaviour of light gauge cold formed steel members comparison of i...eSAT Journals
Abstract Light – gauge steel evolved as a building material in the 1930’s and reached large scale usage only after the Second World War. In comparison with conventional steel construction, where standard hot rolled shapes are used, the cold formed light gauge steel structures are relatively new development. This paper presents a study on behaviour and economical of cold formed steel (CFS) built up channel section using different codes. This paper provides an experimental investigation for the bending strength of Cold – Formed light gauge steel plain (stiffened) rectangular sections. The test specimens were brake pressed from high strength structural steel sheets. In addition, the test strengths were compared with the design strengths calculated using the Indian Standard and Euro codes Specification for Cold –Formed steel structures. Flexural members are linear members in which axial forces act to cause elongation (stretch). The theoretical data are calculated using Indian Standard code IS 801-1975 and the section properties of the specimens are obtained using IS 811-1975. The specimens are designed under uniformly distributed loading with simply supported condition. The research project aims to provide which code of practice given more economical, high bending strength, more load carrying capacity and high flexural strength. The studies reveal that the theoretical investigations limit state methods (SI method) have high bending strength, high load caring capacity, maximum deflection and minimum local buckling& distortional buckling compare to the other codes. Keywords: Cold formed steel, built up channel section, limit state method, working stress method, bending strength, deflection
The document summarizes literature on expandable and collapsible winding mandrels. It begins with an introduction to winding mandrels and their importance in the coil winding process. It then reviews 14 US patents related to expandable and collapsible winding mandrel designs. Common features of mandrels are identified including dividing plates, winding baffles, and supporting bars. The review analyzes and classifies the patents based on whether the mandrel is expandable or collapsible. Expandable mandrels are expanded before winding and collapsed after to remove the coil. Collapsible mandrels are wound on and then collapsed to remove the coil. The conclusion proposes changing from a circular to elliptical mandrel design to reduce transformer size by 15% while maintaining
Experimental investigation on triple blended scc filled steel tubes with and ...eSAT Journals
Abstract
Concrete filled steel tubular columns are gaining its popularity in engineering practice. However, local buckling is the main criteria which effects on strength and ductility for the composite columns. In order to enhance their overall performance, one of the most effective measures is to provide stiffeners for the steel tubes. In the present research, experimental studies have been devoted to investigating the behavior of self-compacting Concrete Filled Steel Tube (CFST) stub columns strengthened by single or double stiffeners. A total of 36 stub columns specimen under monotonic compression load were tested in order to discover the best configuration of column system where (specimen having zero stiffeners, single stiffener, double stiffeners) each for hollow steel and with SCC in-filled are tested for 7 days, 28 days and 56 days strength with circular cross-sections of dimensions 300mm height x100mm diameter x 2mm thickness. The experimental results indicated that the use of Stiffeners strengthen the CFST has a significant effect on the overall behavior of CFST such as enhancement on its strength and ductility. Also the Stiffeners confinement delays local buckling of steel tube, prevents a sudden strength reduction caused by the local buckling of the steel tube, and increases lateral confinement of the concrete core. It is found that the best configuration of Stiffeners in the Steel tubes is providing it in transverse direction with single and double stiffeners at a height of h/2 and h/3 respectively.
The document discusses static and fatigue analysis of a modified multi-leaf spring used in light commercial vehicle (LCV) suspension systems. Finite element analysis is performed on the modified 7-leaf steel spring model to analyze stress, deflection, and stiffness. Fatigue life of the modified spring is also predicted using fatigue analysis software. The results from the finite element and fatigue analyses are compared to analytical calculations to validate the model and predicted fatigue life of the modified leaf spring design.
Steel connections are used to join steel members like beams and columns. There are different types of connections classified by connecting medium like bolted, welded, and riveted. Bolted connections are common and cost-effective. Welded connections provide rigidity but require careful welding and inspection. Common connections include single and double plate angle connections for beams to columns, and seated and top-and-bottom angle connections for moments. Proper connections allow complex steel structures to be designed and fabricated.
Torsion & springs strength of materials BY G.DINESHPIRANDinesh Piran-Gdp
The document discusses torsion and springs. It first discusses torsion in rotating shafts used to transmit power in industries. When a shaft twists, it induces shear stress in addition to bending and axial stresses. It then discusses different types of springs used to absorb energy through resilience. Springs can be classified based on the type of resilience (bending or torsion), construction (laminated or helical), and the nature of load carried (compression or tension). Helical springs are further classified as closely or openly coiled. Compression springs have coils that close under load while tension springs have coils that open under load.
Buckling Analysis of Cold Formed Steel Compression Members at Elevated Temper...IJMER
Abstract: Cold-formed steel members have been widely used in residential, industrial and commercial
buildings as primary load bearing structural elements due to their advantages such as higher strength to
weight ratio over the other structural materials such as hot-rolled steel, timber and concrete. However,
they are susceptible to various buckling modes including local and distortional buckling. Fire safety
design of building structures has received greater attention in recent times as fire events can cause loss
of property and lives. Therefore it is essential to understand the fire performance of light gauge coldformed
steel structures under fire conditions. The buckling behavior of cold-formed steel compression
members under fire conditions is not well investigated yet and hence there is a lack of knowledge on the
fire performance of cold-formed steel compression members. Therefore, this paper deals with behavior
of cold formed steel compression member under fire and to analyze the effect of fire on critical buckling
load of compression member. Eigen value analysis for Lipped channel sections made of various
thicknesses and both low and high strength steels was carried out through finite element method. The
ultimate load carrying capacity results from experimental investigation and finite element analyses were
then compared
1) The document describes modeling and analyzing a composite propeller blade for an underwater vehicle using finite element analysis in ANSYS.
2) A propeller model was created in CATIA and meshed in HYPERMESH. Static, modal, and harmonic analyses were performed on aluminum and composite propeller models with varying layer numbers.
3) For the composite propeller, interlaminar shear stresses increased with additional layers while maximum deflections and stresses remained stable. The results for both materials were found to be within elastic limits.
Fabrication of GFRP(composite) leaf springSainathSteve
This provides an introduction to composites and Fabrication of a simple Glass Fiber Reinforced Polymer based Leaf spring. This also describes the advantages of GFRP leafspring compared to steel made leaf spring
This document summarizes the process of forging and provides details on:
- Forging involves working metal under compressive forces like hammering or pressing to obtain a useful shape and improve mechanical properties.
- Hammer forging focuses forces on the surface while press forging uses slower compressive forces that increase pressure before release.
- Factors that determine forgeability include the metal's lattice structure, with FCC being most forgeable, followed by BCC then HCP, and higher temperatures also improve forgeability.
- Common metals suitable for forging include aluminum alloys, magnesium alloys, copper alloys, and carbon steels. Forging temperatures must be above the metal's recrystallization point
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Revision of Industry Residence with Two Different Materials Considering Const...ijtsrd
In our study we are performing analysis of such structure considering material other that General steel hot rolled . In this study we are analyzing the same structure with same loading conditions using Cold formed steel structure. In this study we are comparing both the structures for lateral pressure using analysis tool Staad.pro which is advance analysis tool with optimization option for cost effective design. Comparative analysis was done while creating a structure using Hot rolled Steel sections and Cold Formed Steel CFS and results were presented on Shear Force, Axial Force, Support Reaction, Node Deflection and Cost analysis where Cold formed Steel was found durable in every case. Amit Kumar Tiwari | Abay Kumar Jha | Rohit jain "Revision of Industry Residence with Two Different Materials Considering Construction Framework using Staad.Pro" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-6 , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd33417.pdf Paper Url: https://www.ijtsrd.com/engineering/civil-engineering/33417/revision-of-industry-residence-with-two-different-materials-considering-construction-framework-using-staadpro/amit-kumar-tiwari
This document discusses steel sections used in Pakistani structures. It describes the classification of steel by carbon content and introduces common structural shapes like I-beams, channels, angles, tubes. It provides examples of famous Pakistani steel structures and lists major steel mills. The main steel shapes used are described as bars, angles, channels, T-sections, I-beams and tubes.
This document presents a study on using sliding mode control to regulate the speed of a DC motor. It begins with background on variable structure systems and sliding mode control. It then describes the mathematical model of a typical DC motor. The controller design section explains the sliding mode control approach, including defining a sliding surface and the control law. Simulation results are presented showing the motor speed and control voltage signal over time for different sliding mode controllers. The document concludes the sliding mode control technique provides robustness and can stabilize uncertain systems while rejecting disturbances.
The document summarizes a study that mapped the conditions and characteristics of buildings in the Muaro Jambi district of Indonesia. Key findings include:
1. Muaro Jambi has rural settlements, a temple complex, a port and industrial area, and road corridors.
2. The study identified land use patterns and found the largest portions were large-scale plantations, small-scale plantations, and degraded and peat forests.
3. The mapping will provide baseline data for drafting local building regulations tailored to Muaro Jambi's sociolegal conditions and existing building stock.
This document summarizes research on using magnetic induction heating to simultaneously heat and stir mixtures of carboxylic acid components for preparing eutectic mixtures. Eutectic mixtures have the lowest possible melting point, so conventional heating and stirring methods did not allow for proper mixing. The researchers applied magnetic induction heating, which provides simultaneous heating and stirring. They found that using this method, the melting points of different acid-acid mixtures were the same each time, showing uniform mixing had occurred. Magnetic induction heating is an accurate, fast and energy-efficient technique for preparing eutectic mixtures.
This document discusses using Gamma tone Frequency Cepstral Coefficients (GFCC) and K-means clustering to identify singers based on their voice. It begins by explaining that MFCC is not accurate in noisy environments, while GFCC performs well in both clean and noisy audio. The process involves extracting GFCC features from the audio, using K-means clustering to group similar voices into clusters, and dynamic time warping for authentication. Feature extraction with GFCC involves preprocessing, framing, windowing, computing the discrete Fourier transform, applying a gamma tone filter bank, logarithmic compression, and discrete cosine transformation to generate feature vectors. K-means clustering is then used to group the feature vectors from similar voices into clusters to identify
This document analyzes helical compression springs used in the rear suspension of two-wheeled vehicles. It presents analytical calculations and finite element analysis to determine stresses and deflections in springs made of hard carbon steel and chrome vanadium steel with circular and rectangular cross-sections under various loads. The results show that chrome vanadium steel springs have lower deflections than hard carbon steel springs under the same loads. Chrome vanadium steel is also concluded to be a better replacement material due to its lower cost and ability to work efficiently with less maintenance.
Modification of a Two Wheeler Suspension System using FeaIJERA Editor
A spring is defined as an elastic body, whose function is to compress when loaded and to recover its original
shape when the load is removed. A spring is a flexible element used to exert a force or a torque and, at the same
time, to store energy. The force can be a linear push or pull, or it can be radial. In two wheelers we used to see
helical suspension at the front and rear tyres on both sides. But the new model bikes are replacing the rear
double suspension with the single heavy duty suspension. Our project deals with the design and modification of
the suspension system and analyzing that can we replace one heavy duty spring in the place of double springs.
For this we have conducted structural analysis by varying the spring material and keeping base material same.
By seeing the results, Comparison is done for four materials to validate better material for suspension system by
doing analysis on spring with help of ANSYS software for find out which material is best for the suspension
system.
And also we modified the actual model and also conducting the same analysis on it and validating that which
model is better.
The modeling done in Creo-5 and analysis is done Ansys package.
Analysis and Estimation of Stiffness of Outer Race of Aircraft Bearingspaperpublications3
The document analyzes and estimates the stiffness of the outer race of aircraft bearings. It describes how a bearing outer race was modeled and analyzed in CREO and ANSYS software to determine its deflection and stiffness when subjected to radial loads. The results found a stiffness value of 769.23 kN/mm which was verified through theoretical calculations to be within acceptable limits for aircraft bearing materials.
This technical note investigates the causes of rotor bending in turbines and a thermal straightening method called hot spotting. Hot spotting was performed seven times on a bent rotor using different temperatures and times. The results showed that 690±20°C for 210 seconds provided noticeable straightening without affecting mechanical properties. Finite element modeling also simulated heat distribution under different conditions to determine optimal restraint around the hot spot area.
This document discusses the selection of forging equipment and stock size for open and closed die forging. It begins by classifying forging equipment into work-restricted and stroke-restricted machines such as hammers, presses, and hydraulic presses. It then explains open and closed die forging processes and considerations for die design such as flash, gutter, draft angles, and variation of stroke with load. The document concludes by providing design considerations for blocker, finisher, trim tools, and punches.
Flexural behaviour of light gauge cold formed steel members comparison of i...eSAT Journals
Abstract Light – gauge steel evolved as a building material in the 1930’s and reached large scale usage only after the Second World War. In comparison with conventional steel construction, where standard hot rolled shapes are used, the cold formed light gauge steel structures are relatively new development. This paper presents a study on behaviour and economical of cold formed steel (CFS) built up channel section using different codes. This paper provides an experimental investigation for the bending strength of Cold – Formed light gauge steel plain (stiffened) rectangular sections. The test specimens were brake pressed from high strength structural steel sheets. In addition, the test strengths were compared with the design strengths calculated using the Indian Standard and Euro codes Specification for Cold –Formed steel structures. Flexural members are linear members in which axial forces act to cause elongation (stretch). The theoretical data are calculated using Indian Standard code IS 801-1975 and the section properties of the specimens are obtained using IS 811-1975. The specimens are designed under uniformly distributed loading with simply supported condition. The research project aims to provide which code of practice given more economical, high bending strength, more load carrying capacity and high flexural strength. The studies reveal that the theoretical investigations limit state methods (SI method) have high bending strength, high load caring capacity, maximum deflection and minimum local buckling& distortional buckling compare to the other codes. Keywords: Cold formed steel, built up channel section, limit state method, working stress method, bending strength, deflection
The document summarizes literature on expandable and collapsible winding mandrels. It begins with an introduction to winding mandrels and their importance in the coil winding process. It then reviews 14 US patents related to expandable and collapsible winding mandrel designs. Common features of mandrels are identified including dividing plates, winding baffles, and supporting bars. The review analyzes and classifies the patents based on whether the mandrel is expandable or collapsible. Expandable mandrels are expanded before winding and collapsed after to remove the coil. Collapsible mandrels are wound on and then collapsed to remove the coil. The conclusion proposes changing from a circular to elliptical mandrel design to reduce transformer size by 15% while maintaining
Experimental investigation on triple blended scc filled steel tubes with and ...eSAT Journals
Abstract
Concrete filled steel tubular columns are gaining its popularity in engineering practice. However, local buckling is the main criteria which effects on strength and ductility for the composite columns. In order to enhance their overall performance, one of the most effective measures is to provide stiffeners for the steel tubes. In the present research, experimental studies have been devoted to investigating the behavior of self-compacting Concrete Filled Steel Tube (CFST) stub columns strengthened by single or double stiffeners. A total of 36 stub columns specimen under monotonic compression load were tested in order to discover the best configuration of column system where (specimen having zero stiffeners, single stiffener, double stiffeners) each for hollow steel and with SCC in-filled are tested for 7 days, 28 days and 56 days strength with circular cross-sections of dimensions 300mm height x100mm diameter x 2mm thickness. The experimental results indicated that the use of Stiffeners strengthen the CFST has a significant effect on the overall behavior of CFST such as enhancement on its strength and ductility. Also the Stiffeners confinement delays local buckling of steel tube, prevents a sudden strength reduction caused by the local buckling of the steel tube, and increases lateral confinement of the concrete core. It is found that the best configuration of Stiffeners in the Steel tubes is providing it in transverse direction with single and double stiffeners at a height of h/2 and h/3 respectively.
The document discusses static and fatigue analysis of a modified multi-leaf spring used in light commercial vehicle (LCV) suspension systems. Finite element analysis is performed on the modified 7-leaf steel spring model to analyze stress, deflection, and stiffness. Fatigue life of the modified spring is also predicted using fatigue analysis software. The results from the finite element and fatigue analyses are compared to analytical calculations to validate the model and predicted fatigue life of the modified leaf spring design.
Steel connections are used to join steel members like beams and columns. There are different types of connections classified by connecting medium like bolted, welded, and riveted. Bolted connections are common and cost-effective. Welded connections provide rigidity but require careful welding and inspection. Common connections include single and double plate angle connections for beams to columns, and seated and top-and-bottom angle connections for moments. Proper connections allow complex steel structures to be designed and fabricated.
Torsion & springs strength of materials BY G.DINESHPIRANDinesh Piran-Gdp
The document discusses torsion and springs. It first discusses torsion in rotating shafts used to transmit power in industries. When a shaft twists, it induces shear stress in addition to bending and axial stresses. It then discusses different types of springs used to absorb energy through resilience. Springs can be classified based on the type of resilience (bending or torsion), construction (laminated or helical), and the nature of load carried (compression or tension). Helical springs are further classified as closely or openly coiled. Compression springs have coils that close under load while tension springs have coils that open under load.
Buckling Analysis of Cold Formed Steel Compression Members at Elevated Temper...IJMER
Abstract: Cold-formed steel members have been widely used in residential, industrial and commercial
buildings as primary load bearing structural elements due to their advantages such as higher strength to
weight ratio over the other structural materials such as hot-rolled steel, timber and concrete. However,
they are susceptible to various buckling modes including local and distortional buckling. Fire safety
design of building structures has received greater attention in recent times as fire events can cause loss
of property and lives. Therefore it is essential to understand the fire performance of light gauge coldformed
steel structures under fire conditions. The buckling behavior of cold-formed steel compression
members under fire conditions is not well investigated yet and hence there is a lack of knowledge on the
fire performance of cold-formed steel compression members. Therefore, this paper deals with behavior
of cold formed steel compression member under fire and to analyze the effect of fire on critical buckling
load of compression member. Eigen value analysis for Lipped channel sections made of various
thicknesses and both low and high strength steels was carried out through finite element method. The
ultimate load carrying capacity results from experimental investigation and finite element analyses were
then compared
1) The document describes modeling and analyzing a composite propeller blade for an underwater vehicle using finite element analysis in ANSYS.
2) A propeller model was created in CATIA and meshed in HYPERMESH. Static, modal, and harmonic analyses were performed on aluminum and composite propeller models with varying layer numbers.
3) For the composite propeller, interlaminar shear stresses increased with additional layers while maximum deflections and stresses remained stable. The results for both materials were found to be within elastic limits.
Fabrication of GFRP(composite) leaf springSainathSteve
This provides an introduction to composites and Fabrication of a simple Glass Fiber Reinforced Polymer based Leaf spring. This also describes the advantages of GFRP leafspring compared to steel made leaf spring
This document summarizes the process of forging and provides details on:
- Forging involves working metal under compressive forces like hammering or pressing to obtain a useful shape and improve mechanical properties.
- Hammer forging focuses forces on the surface while press forging uses slower compressive forces that increase pressure before release.
- Factors that determine forgeability include the metal's lattice structure, with FCC being most forgeable, followed by BCC then HCP, and higher temperatures also improve forgeability.
- Common metals suitable for forging include aluminum alloys, magnesium alloys, copper alloys, and carbon steels. Forging temperatures must be above the metal's recrystallization point
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Revision of Industry Residence with Two Different Materials Considering Const...ijtsrd
In our study we are performing analysis of such structure considering material other that General steel hot rolled . In this study we are analyzing the same structure with same loading conditions using Cold formed steel structure. In this study we are comparing both the structures for lateral pressure using analysis tool Staad.pro which is advance analysis tool with optimization option for cost effective design. Comparative analysis was done while creating a structure using Hot rolled Steel sections and Cold Formed Steel CFS and results were presented on Shear Force, Axial Force, Support Reaction, Node Deflection and Cost analysis where Cold formed Steel was found durable in every case. Amit Kumar Tiwari | Abay Kumar Jha | Rohit jain "Revision of Industry Residence with Two Different Materials Considering Construction Framework using Staad.Pro" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-6 , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd33417.pdf Paper Url: https://www.ijtsrd.com/engineering/civil-engineering/33417/revision-of-industry-residence-with-two-different-materials-considering-construction-framework-using-staadpro/amit-kumar-tiwari
This document discusses steel sections used in Pakistani structures. It describes the classification of steel by carbon content and introduces common structural shapes like I-beams, channels, angles, tubes. It provides examples of famous Pakistani steel structures and lists major steel mills. The main steel shapes used are described as bars, angles, channels, T-sections, I-beams and tubes.
This document presents a study on using sliding mode control to regulate the speed of a DC motor. It begins with background on variable structure systems and sliding mode control. It then describes the mathematical model of a typical DC motor. The controller design section explains the sliding mode control approach, including defining a sliding surface and the control law. Simulation results are presented showing the motor speed and control voltage signal over time for different sliding mode controllers. The document concludes the sliding mode control technique provides robustness and can stabilize uncertain systems while rejecting disturbances.
The document summarizes a study that mapped the conditions and characteristics of buildings in the Muaro Jambi district of Indonesia. Key findings include:
1. Muaro Jambi has rural settlements, a temple complex, a port and industrial area, and road corridors.
2. The study identified land use patterns and found the largest portions were large-scale plantations, small-scale plantations, and degraded and peat forests.
3. The mapping will provide baseline data for drafting local building regulations tailored to Muaro Jambi's sociolegal conditions and existing building stock.
This document summarizes research on using magnetic induction heating to simultaneously heat and stir mixtures of carboxylic acid components for preparing eutectic mixtures. Eutectic mixtures have the lowest possible melting point, so conventional heating and stirring methods did not allow for proper mixing. The researchers applied magnetic induction heating, which provides simultaneous heating and stirring. They found that using this method, the melting points of different acid-acid mixtures were the same each time, showing uniform mixing had occurred. Magnetic induction heating is an accurate, fast and energy-efficient technique for preparing eutectic mixtures.
This document discusses using Gamma tone Frequency Cepstral Coefficients (GFCC) and K-means clustering to identify singers based on their voice. It begins by explaining that MFCC is not accurate in noisy environments, while GFCC performs well in both clean and noisy audio. The process involves extracting GFCC features from the audio, using K-means clustering to group similar voices into clusters, and dynamic time warping for authentication. Feature extraction with GFCC involves preprocessing, framing, windowing, computing the discrete Fourier transform, applying a gamma tone filter bank, logarithmic compression, and discrete cosine transformation to generate feature vectors. K-means clustering is then used to group the feature vectors from similar voices into clusters to identify
This document proposes a new approach to compressed image steganography using wavelet transform. The method embeds a compressed payload image within a cover image using discrete wavelet transform (DWT) for image compression and discrete Fourier transform (DFT) to select pixel locations in the cover image. Five test cases of the approach are described and evaluated. In the first case, DWT is applied to the payload image to get 32x32 approximate coefficients, DFT is applied to the cover image to select pixel locations below a threshold, and the coefficients replace the selected pixel values to create the stego-image. The other cases vary the DWT level, threshold value, and image sizes. Results show the stego-image quality
This document describes a new algorithm for blood vessel extraction from retinal fundus images based on thresholding the maximum filter response (MFR). Gaussian derivative filters are applied to the images to enhance the blood vessels. The maximum response across filter scales is used. Entropy-based thresholding of the normalized MFR image is then used to segment the blood vessels. The algorithm is tested on 23 images from a publicly available retinal image database, achieving good extraction of normal and abnormal vessels of different sizes.
This document discusses a study on using non-monetary incentives to improve service delivery in public institutions in Tharaka Nithi County, Kenya. The study aimed to examine the effects of tangible rewards, employee recognition, workplace opportunities, and job flexibility on service delivery. It utilized a descriptive research design and collected data through questionnaires and interviews with employees and managers at Chuka University. The findings revealed that the institution did not extensively apply non-monetary incentives to improve service delivery, though limited recognition was used. Most respondents felt incentives were needed to reduce poor service delivery instances. The study recommended recognition, job flexibility, and tangible rewards as low-cost ways to incentivize better performance.
Causes of Delay in Construction of Bridge GirdersIOSR Journals
The document discusses causes of delay in the construction of bridge girders for a three-span bridge over the Sabarmati River in Gandhinagar, Gujarat, India. It analyzes the planned versus actual construction schedules, finding total delays of 75 days. Major causes of delay included insufficient equipment capacity, lack of materials and skilled labor, delays in design approvals, labor issues, and use of conventional construction methods. The document categorizes common causes of construction delays and identifies responsible parties.
The document describes a new efficient shower water heater design that uses a novel heat transfer method. Key points:
- The design aims to significantly reduce power consumption compared to conventional electric water heaters by heating water in small volumes directly in the shower head rather than a large reservoir.
- Coiled heating elements housed in small tubes are placed inside the shower head openings so that only a few milliliters of water pass through and are heated at a time.
- This micro heating approach is expected to exponentially reduce the power needed compared to traditional systems that heat larger volumes of water at once.
- Other benefits may include lower hazards, portability, lighter weight, and enabling the use of small renewable power
This document summarizes a study that measured the field strength distribution of a 91.5 MHz FM radio signal across Ekiti State, Nigeria. Field strength, location coordinates, and distance from transmitter were measured along four routes moving away from the broadcast station. The path loss along each route was calculated using Friis and Okumura-Hata propagation models and compared to measured values. Okumura-Hata provided closer predictions, with a mean error of 2.68dB across routes, suggesting it is more suitable for modeling VHF path loss in Ekiti State when a 2.68dB loss factor is included.
This document summarizes a study that investigated the formulation of neem seed oil and jatropha seed oil with antimony dialkyldithiocarbohate (ADTC) additives for use as bio-based lubricants. Tribological tests were conducted using a four-ball tribometer to evaluate the lubricity performance of the two oil formulations. The results showed that the jatropha seed oil formulation had lower friction coefficients and better wear protection under the test conditions, indicating it performed better as a lubricant. The study concluded that jatropha seed oil with ADTC additives showed potential for use as an environmentally-friendly bio-based lubricant.
This document summarizes a case study that used the Canadian Seismic Screening Method to evaluate 37 reinforced concrete buildings in Ahlat, Turkey. The screening method uses 8 parameters to calculate a Structural Index and Non-Structural Index for each building, which are then combined to determine a Seismic Priority Index. For the study in Ahlat, 14% of buildings were rated as low priority, 41% as medium priority, 35% as high priority, and 10% as very risky priority. The screening method provided a fast way to assess the seismic risk of numerous buildings and identify which should undergo more detailed evaluation.
This document discusses the use of magnetorheological smart dampers to strengthen structures against vibrations. A magnetorheological damper was fabricated using magnetorheological fluid and a magnetic coil. Testing showed that the damper effectively attenuates vibration amplitudes and can generate large damping forces by varying the current input to the magnetic coil. Such smart dampers can be installed in tall buildings, towers, and other structures to strengthen them against wind and seismic loads using semi-active control, improving stability and preventing catastrophic failures. The document concludes that smart dampers are capable of producing very large damping forces by varying the input current to the magnetic coil, providing semi-active control that can stabilize structures subjected to varying loads.
1) The document derives the equations describing the interaction forces between two identical cylinders spinning around their stationary and parallel axes in an ideal fluid.
2) It is found that the fluid velocity field can be determined by solving the Laplace equation, and that the pressure field can then be obtained from the velocity field using Bernoulli's equation.
3) By integrating the pressure around the surface of each cylinder, it is shown that the cylinders will repel or attract each other in inverse relation to their separation distance, depending on whether their directions of rotation are the same or opposite.
This document compares communication links between optical fiber and VSAT for offshore platforms. It discusses that optical fiber provides higher speeds, better signal quality, and higher reliability than VSAT, but has higher upfront costs. VSAT can cover larger distances at a lower cost, but has lower speeds and quality. For clusters of platforms near shore, fiber is often preferable due to its performance, but for wide coverage VSAT may be more cost effective despite its limitations. The key factors in choosing a link include cost, capacity, reliability, backup options, and services required.
Computer aided environment for drawing (to set) fill in the blank from given ...IOSR Journals
Abstract: In this paper, we present Development of computer aided environment for drawing (to set) fill in the
blanks that can generate for given paragraph. The System finds fill in the blanks, blanking key generates from
the selected statement. Syntactic and lexical features are used in this process. NLP parser is used, part of speech
taggers are applied on each of these sentences to encode necessary information.
We present our work in designing and implementing the system which generate the blanks. The System is
developed in Java using JDBC which is open source.
Keyword: Natural Language Processing NLP, Key selection, POS tagging, Sentence selection
This document discusses image superresolution techniques in both the spatial and frequency domains. It compares a spatial domain algorithm by Keren et al. to a frequency domain algorithm by Vandewalle et al. for image registration. The spatial domain algorithm more accurately estimates shift and rotation parameters, especially when images contain strong directionality. For image reconstruction, it compares interpolation, iterative backpropagation, and a robust super resolution algorithm. Experimental results show the spatial domain approach works better for the application of image superresolution.
“Evaluation of Sewing Performance of Plain Twill and Satin Fabrics Based On S...IOSR Journals
Abstract: Seam strength is an important factor in determining the durability of a garment. Seam strength is
determined by resistance to pulling force and abrasion. Seam tenacity break the fabric or the weakest stitch of
seam. Seam abrasion resistance is the amount of rubbing action needed to wear away stitches in the seam
strength is related to stitch type, thread strength ,thread tension, seam type,seam efficiency, width ,and stitches
per inch.Loop strength of thread is more important to durability the seam need not be stronger than the fabric
being sewn.A triple stitched lapped seam would not be necessary for a pair of corduroy jeans since the fabric
itself is not strong and would wear out before the seam.It is better to have the thread is an overstressed seam
that to damage the fabric.Our project objective is to find the seam of strength by using different type of materials.
This document describes the design and simulation of an AlGaN/GaN high electron mobility transistor (HEMT) on a silicon carbide substrate for low noise applications. Key findings from the simulation of the 0.25 um gate length device include:
1) The device exhibited a minimum noise figure of 0.41 dB and maximum associated gain of 19.95 dB at 10 GHz.
2) It also demonstrated a minimum noise figure of 0.71 dB and maximum associated gain of 17.4 dB at 18 GHz.
3) The device showed a peak extrinsic transconductance of 215 mS/mm and a high current drive capability of 1400 mA/mm, indicating its potential for
This document discusses group consumption modes. It analyzes factors that impact group consumption, including external environmental factors like technological developments enabling new forms of online and offline interactions, as well as internal motivational factors at both the group and individual level. The document then proposes that group consumption modes can be divided into four types based on two dimensions: vertical (group relationship intensity) and horizontal (consumption action period). These four types are instrument-oriented, information-oriented, enjoyment-oriented, and relationship-oriented consumption modes. Finally, the document notes that consumption modes are dynamic and can evolve over time.
Dimensional Optimization of Helical Springs Used in Tractor Seat by FEA and E...IRJET Journal
This document discusses dimensional optimization and failure analysis of helical springs used in tractor seats through finite element analysis (FEA) and experimental testing. It aims to reduce stresses on helical springs under dynamic loading conditions typically experienced in tractor seats.
The study examines the current design of tractor seat helical springs and performs FEA stress analysis, fatigue life analysis, and experimental testing. It also proposes a new spring configuration for the tractor seat to improve spring performance. Results from analytical stress calculations, FEA stress modeling, and experimental fatigue testing of tension and compression springs are presented and compared to evaluate which spring design provides better stress distribution and longer fatigue life.
IRJET- Study Analysis of Metal Bending in a Sheet Metal using Finite Elem...IRJET Journal
This document summarizes a study that analyzed the bending of aluminum sheet metal and aluminum sandwich panels with different core materials using finite element analysis software. Sandwich panels with cores of polypropylene, polystyrene, carbon fiber, and glass fiber were modeled and their deformation and stress distributions under bending forces were compared to a monolithic aluminum sheet. The sandwich panels exhibited better bending resistance and damage resistance than the aluminum sheet. Overall, sandwich panels with the same thickness are recommended over aluminum sheets due to their better resistance to external forces. The study aims to find alternative materials to aluminum for use in aircraft to improve resistance to impacts from bird strikes.
IRJET- Static and Dynamic Analysis of a Two Wheeler Shock Absorber using ...IRJET Journal
This document presents a study analyzing the static and dynamic performance of a two-wheeler shock absorber using different materials for the helical coil spring. A 3D model of a shock absorber is created in SolidWorks. Structural, modal, frequency response, and transient analyses are performed to evaluate stresses, displacements, natural frequencies, and dynamic response under various loading conditions. Five different materials - stainless steel, carbon steel, phosphor bronze, beryllium copper, and titanium alloy - are considered for the spring. The analyses aim to determine the best material for the spring to improve the shock absorber's performance.
Energy Absorption Characteristics of Thin Walled Metallic and Foam Filled Tub...IRJET Journal
This document discusses a numerical study comparing the energy absorption characteristics of thin-walled metallic tubular structures with different cross-sectional geometries, both empty and foam-filled. Finite element models of circular, triangular, hexagonal and square tubes undergoing quasi-static axial crushing were created and analyzed. The results show that circular tubes absorbed the most energy of the empty metallic tubes, while foam-filled tubes had higher energy absorption than empty tubes of the same geometry.
The document presents a student's design and analysis project on helical springs made of different materials using ANSYS software. The student, K. Raghunatha, conducted modeling in CATIA and analysis in ANSYS to compare the stress and deflection of springs made of stainless steel, oil-tempered spring steel, and chrome silicon material. The results showed that the chrome silicon material had the minimum deformation, equivalent stress, and equivalent elastic strain, making it the optimal material. A parametric study was also performed by varying the pitch, number of coils, and wire diameter of the chrome silicon spring, finding the optimal parameters that reduced stress and deflection.
Rocker arms are part of the valve-actuating mechanism. A rocker arm is designed to pivot on a pivot
pin or shaft that is secured to a bracket. The bracket is mounted on the cylinder head. One end of a
rocker arm is in contact with the top of the valve stem, and the other end is actuated by the camshaft.
In installations where the camshaft is located below the cylinder head, the rocker arms
are actuated by pushrods. The lifters have rollers which are forced by the valve springs to follow the
profiles of the cams. Failure of rocker arm is a measure concern as it is one of the important
components of push rod IC engines.Present work finds the various stresses under extreme load
condition. For this we are modeling the arm using design software and the stressed regions are
found out usingAnsys software. Here in this thesis we are observing that by changing different
materials how the stresses are varying in the rocker arm under extreme load condition. And after
comparing results we are proposing best suitable material for the rocker arm under extreme load conditions.
Determination of Buckling Loads of Wave Spring Using ANSYSIJRES Journal
Special performance characteristics are individually built into each spring to satisfy a variety of precise operating conditions. Typically, a wave spring will occupy an externally small area for the amount of work it performs. The present work deals with the structural analysis of wave and coil spring by modeling the structural behavior of these springs using three dimensional finite elements (FE) software. The design of spring in suspension system is very important. In this work a wave type of spring is designed and a 3D model is created using CREO software. The model is also varied by changing the length of the spring. Structural analysis has been conducted on the wave spring by varying thickness and number of turns. For the analysis, loads are bike weight with single and two persons. The buckling load is then estimated for both Wave spring and coil spring with the same parameters.
Study on the mechanism of force calculations in flow forming a reviewIAEME Publication
The document reviews the mechanism of force calculations in flow forming, which is a metal forming process that elongates a hollow preform into a thin tube using rotating rollers. It discusses different types of flow forming processes, analyzes the forces involved, and outlines applications in industries like aerospace, automotive, and defense. Research on modeling the forces is also examined, showing most work has focused on modeling tangential forces and comparing analytical and finite element simulations.
Study on the mechanism of force calculations in flow forming a reviewIAEME Publication
This document summarizes a research article on the mechanism of force calculations in flow forming. Flow forming is a metal forming process that elongates a hollow preform into a thin tube over a rotating mandrel using rollers. There are various types of flow forming classified based on how the preform is fixed and the positioning of the rollers. Staggered roll flow forming uses three rollers offset axially and radially with different geometries and functions. In-line flow forming uses three or four rolls positioned directly above one another both axially and radially. The document reviews research on modeling and simulating the flow forming process using finite element analysis to optimize process parameters and reduce computational time.
Rocker arms are part of the valve-actuating mechanism. A rocker arm is designed to pivot on a pivot pin or shaft that is secured to a bracket. The bracket is mounted on the cylinder head. One end of a rocker arm is in contact with the top of the valve stem, and the other end is actuated by the camshaft. In installations where the camshaft is located below the cylinder head, the rocker arms are actuated by pushrods. The lifters have rollers which are forced by the valve springs to follow the profiles of the cams. Failure of rocker arm is a measure concern as it is one of the important components of push rod IC engines.Present work finds the various stresses under extreme load condition. For this we are modeling the arm using design software and the stressed regions are found out usingAnsys software. Here in this thesis we are observing that by changing different materials how the stresses are varying in the rocker arm under extreme load condition. And after comparing results we are proposing best suitable material for the rocker arm under extreme load conditions.
Investigation on Mechanical Properties of AL6061 Alloy Processed by FSWijtsrd
The aim of this experiment was to improve the mechanical properties of 6061 aluminium alloys by friction stir processing FSP , a solid-state technique for micro structural modification using the heat from a friction and stirring. The Aluminium alloy 6061 is widely used in the fabrication of lightweight structures with high strength-to-weight ratio and good corrosion resistance. Welding is main fabrication method of 6061 alloy for manufacturing various engineering components. Friction stir welding FSW is a recently developed solid state welding process to overcome the problems encountered in fusion welding. This process uses a non-consumable tool to generate frictional heat on the abutting surfaces. The welding parameters, such as tool pin profile, rotational speed, welding speed and axial force, play major role in determining the micro structure and corrosion resistance of welded joint. In this work a central composite design with two different speeds, traverse speeds and Four tools has been used to minimize the experimental conditions. B. S. Bharadwaj | N. Phani Raja Rao "Investigation on Mechanical Properties of AL6061 Alloy Processed by FSW" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-6 , October 2018, URL: http://www.ijtsrd.com/papers/ijtsrd18802.pdf
IRJET- Piezoelectric Power Generation in Automotives by using Honeycomb S...IRJET Journal
This document discusses the design and analysis of a non-pneumatic tire with a hexagonal honeycomb structure to harvest energy using piezoelectric materials. It provides a literature review on previous studies analyzing honeycomb spoke structures for non-pneumatic tires. The document then introduces the history and development of tires, from early wooden wheels to the modern pneumatic and non-pneumatic designs. Finite element analysis using ANSYS is performed to study stresses and deformation on the hexagonal honeycomb spoke structure under static and dynamic loading conditions. The goal is to optimize the design to minimize stresses from cyclic loading while driving, in order to improve fatigue resistance.
An Overview of Design and Analysis of Rocker ArmIRJET Journal
This document summarizes research on the design and analysis of rocker arms. It discusses how rocker arms are used to transfer motion from camshafts to engine valves. Finite element analysis is used to model rocker arms and analyze stresses. Different materials are analyzed to reduce stresses and increase durability, including steel, aluminum, composites, and polymers. Studies analyzed stresses on rocker arms made of various materials and identified optimal materials to increase strength while reducing weight. Composite materials showed potential to reduce stresses compared to steel.
This project is the design and construction of double acting hacksaw for Cutting wood and metal to different length. The power is given by a motor it drives the pulley which holds the main screw. The main screw holds two connecting rods. The other ends of the connecting rods are connected to the frame of the hack saws. The hacksaws are constrained to move in a straight path with the help of sliders. The frame is designed to provide the necessary motion . In this double acting hacksaw machine we can able to cut materials such as wood, steel, etc. This machine makes the cutting operation much easier and also it reduces the production time. Since two work pieces can be cut at the same time the total time is also reduced. The handling of the machine is much simple.
IRJET- Review on Materials used in Windmill Blade DesignIRJET Journal
This document summarizes materials used for wind turbine blade design. It discusses how composite materials are commonly used for blades and nacelles because they offer benefits like high stiffness, low density, and high fatigue life. The most important part of a wind turbine is the blade, which harnesses wind to produce energy, so the materials used must be efficient and durable. Composite materials have become widely used by manufacturers. The document also reviews different studies on materials used for blades and concludes that composites with carbon fibers provide the best combination of properties like strength and stiffness for large, offshore wind turbines.
This document provides an overview of steel structure design. It discusses the types of steel structures like truss, frame, grid and arch structures. It describes the methodology of steel design using Allowable Strength Design and Load and Resistance Factor Design. It discusses the mechanical properties of steel, concepts of limit state design for beam columns, and connections. It also provides details on the design of beams, including classifications of beams and the main considerations in beam design.
This document summarizes the design and analysis of a disc brake using finite element analysis. It begins with an introduction to brake classifications and an overview of disc brake components and operation. The author then describes modeling a disc brake in Pro-E and analyzing it using finite element analysis to study thermal effects and structural stresses under different operating conditions. Four materials were analyzed: nickel chrome steel, aluminum alloy, cast iron, and carbon reinforced polymer. The results showed carbon reinforced polymer had the best performance with stresses within limits and lower vibrations and weight. Therefore, the summary concludes carbon reinforced polymer is the best material for disc brakes.
Crash Analysis And Design of Multi-Cell Octagonal S-Shape Members Under Axial...IRJESJOURNAL
Abstract : Crashworthiness of the structures used in automotive is widely being addressed as it is defining the safety. The present article aims to investigate crushing performance under axial and oblique impact performed under 10°, 20° and 30° for different cross-section configurations of S-shaped longitudinal members. Modeling and numerical analysis are carried out using finite element code LS-DYNA. The model was validated using experimental data. The complex proportional assessment (COPRAS) method is used to provide optimized alternative design by considering two conflicting criteria, energy absorption (EA) and peak crushing force (PCF). The results indicate that the structures (at which four blades connect the outer and the inner walls) with inner reinforcing blades have a high crash performance than the others (without connecting blades). Besides, the blades in multi-cell members, which connect the middle of edges (T4), lead to superior response in comparison with the other ones (which connect corners). Finally, dimensions (the wall thickness and the distance of inner and outer tubes) of T4 are optimized by design of experiment and response surface methodology techniques
Determination of Fatigue Life of Surface Propeller by Using Finite Element An...sawan kumar
This document summarizes research on modeling and analyzing the fatigue life of a surface propeller using finite element analysis. The propeller was modeled in CATIA and analyzed in ABAQUS to determine stresses and fatigue life. Static structural testing was conducted by varying material properties, and fatigue analysis was performed to analyze the safety factor. Carbon UD/epoxy composite was identified as the best performing material based on the static and fatigue analyses, as it experienced less stress than aluminum. The analyses showed that a composite material propeller would have a longer fatigue life than a metal propeller.
The document describes the design and construction of a rod and yoke connection. It includes stress analysis calculations for tensile, compressive, and shear stresses when a load of 7500 lbs is applied. Dimensions and materials are selected for the rod, yoke, and pin based on the AISI C1040 annealed steel. Factors of safety are calculated based on the ultimate and yield strengths of the material. The rod, yoke, and pin are modeled in 3D and machining processes are planned for construction of the physical connection.
This document provides a technical review of secure banking using RSA and AES encryption methodologies. It discusses how RSA and AES are commonly used encryption standards for secure data transmission between ATMs and bank servers. The document first provides background on ATM security measures and risks of attacks. It then reviews related work analyzing encryption techniques. The document proposes using a one-time password in addition to a PIN for ATM authentication. It concludes that implementing encryption standards like RSA and AES can make transactions more secure and build trust in online banking.
This document analyzes the performance of various modulation schemes for achieving energy efficient communication over fading channels in wireless sensor networks. It finds that for long transmission distances, low-order modulations like BPSK are optimal due to their lower SNR requirements. However, as transmission distance decreases, higher-order modulations like 16-QAM and 64-QAM become more optimal since they can transmit more bits per symbol, outweighing their higher SNR needs. Simulations show lifetime extensions up to 550% are possible in short-range networks by using higher-order modulations instead of just BPSK. The optimal modulation depends on transmission distance and balancing the energy used by electronic components versus power amplifiers.
This document provides a review of mobility management techniques in vehicular ad hoc networks (VANETs). It discusses three modes of communication in VANETs: vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and hybrid vehicle (HV) communication. For each communication mode, different mobility management schemes are required due to their unique characteristics. The document also discusses mobility management challenges in VANETs and outlines some open research issues in improving mobility management for seamless communication in these dynamic networks.
This document provides a review of different techniques for segmenting brain MRI images to detect tumors. It compares the K-means and Fuzzy C-means clustering algorithms. K-means is an exclusive clustering algorithm that groups data points into distinct clusters, while Fuzzy C-means is an overlapping clustering algorithm that allows data points to belong to multiple clusters. The document finds that Fuzzy C-means requires more time for brain tumor detection compared to other methods like hierarchical clustering or K-means. It also reviews related work applying these clustering algorithms to segment brain MRI images.
1) The document simulates and compares the performance of AODV and DSDV routing protocols in a mobile ad hoc network under three conditions: when users are fixed, when users move towards the base station, and when users move away from the base station.
2) The results show that both protocols have higher packet delivery and lower packet loss when users are either fixed or moving towards the base station, since signal strength is better in those scenarios. Performance degrades when users move away from the base station due to weaker signals.
3) AODV generally has better performance than DSDV, with higher throughput and packet delivery rates observed across the different user mobility conditions.
This document describes the design and implementation of 4-bit QPSK and 256-bit QAM modulation techniques using MATLAB. It compares the two techniques based on SNR, BER, and efficiency. The key steps of implementing each technique in MATLAB are outlined, including generating random bits, modulation, adding noise, and measuring BER. Simulation results show scatter plots and eye diagrams of the modulated signals. A table compares the results, showing that 256-bit QAM provides better performance than 4-bit QPSK. The document concludes that QAM modulation is more effective for digital transmission systems.
The document proposes a hybrid technique using Anisotropic Scale Invariant Feature Transform (A-SIFT) and Robust Ensemble Support Vector Machine (RESVM) to accurately identify faces in images. A-SIFT improves upon traditional SIFT by applying anisotropic scaling to extract richer directional keypoints. Keypoints are processed with RESVM and hypothesis testing to increase accuracy above 95% by repeatedly reprocessing images until the threshold is met. The technique was tested on similar and different facial images and achieved better results than SIFT in retrieval time and reduced keypoints.
This document studies the effects of dielectric superstrate thickness on microstrip patch antenna parameters. Three types of probes-fed patch antennas (rectangular, circular, and square) were designed to operate at 2.4 GHz using Arlondiclad 880 substrate. The antennas were tested with and without an Arlondiclad 880 superstrate of varying thicknesses. It was found that adding a superstrate slightly degraded performance by lowering the resonant frequency and increasing return loss and VSWR, while decreasing bandwidth and gain. Specifically, increasing the superstrate thickness or dielectric constant resulted in greater changes to the antenna parameters.
This document describes a wireless environment monitoring system that utilizes soil energy as a sustainable power source for wireless sensors. The system uses a microbial fuel cell to generate electricity from the microbial activity in soil. Two microbial fuel cells were created using different soil types and various additives to produce different current and voltage outputs. An electronic circuit was designed on a printed circuit board with components like a microcontroller and ZigBee transceiver. Sensors for temperature and humidity were connected to the circuit to monitor the environment wirelessly. The system provides a low-cost way to power remote sensors without needing battery replacement and avoids the high costs of wiring a power source.
1) The document proposes a model for a frequency tunable inverted-F antenna that uses ferrite material.
2) The resonant frequency of the antenna can be significantly shifted from 2.41GHz to 3.15GHz, a 31% shift, by increasing the static magnetic field placed on the ferrite material.
3) Altering the permeability of the ferrite allows tuning of the antenna's resonant frequency without changing the physical dimensions, providing flexibility to operate over a wide frequency range.
This document summarizes a research paper that presents a speech enhancement method using stationary wavelet transform. The method first classifies speech into voiced, unvoiced, and silence regions based on short-time energy. It then applies different thresholding techniques to the wavelet coefficients of each region - modified hard thresholding for voiced speech, semi-soft thresholding for unvoiced speech, and setting coefficients to zero for silence. Experimental results using speech from the TIMIT database corrupted with white Gaussian noise at various SNR levels show improved performance over other popular denoising methods.
This document reviews the design of an energy-optimized wireless sensor node that encrypts data for transmission. It discusses how sensing schemes that group nodes into clusters and transmit aggregated data can reduce energy consumption compared to individual node transmissions. The proposed node design calculates the minimum transmission power needed based on received signal strength and uses a periodic sleep/wake cycle to optimize energy when not sensing or transmitting. It aims to encrypt data at both the node and network level to further optimize energy usage for wireless communication.
The document summarizes a study of different microstrip patch antenna configurations with slotted ground planes. Three antenna designs were proposed and their performance evaluated through simulation: a conventional square patch, an elliptical patch, and a star-shaped patch. All antennas were mounted on an FR4 substrate. The effects of adding different slot patterns to the ground plane on resonance frequency, bandwidth, gain and efficiency were analyzed parametrically. Key findings were that reshaping the patch and adding slots increased bandwidth and shifted resonance frequency. The elliptical and star patches in particular performed better than the conventional design. Three antenna configurations were selected for fabrication and measurement based on the simulations: a conventional patch with a slot under the patch, an elliptical patch with slots
1) The document describes a study conducted to improve call drop rates in a GSM network through RF optimization.
2) Drive testing was performed before and after optimization using TEMS software to record network parameters like RxLevel, RxQuality, and events.
3) Analysis found call drops were occurring due to issues like handover failures between sectors, interference from adjacent channels, and overshooting due to antenna tilt.
4) Corrective actions taken included defining neighbors between sectors, adjusting frequencies to reduce interference, and lowering the mechanical tilt of an antenna.
5) Post-optimization drive testing showed improvements in RxLevel, RxQuality, and a reduction in dropped calls.
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20240609 QFM020 Irresponsible AI Reading List May 2024
L012548291
1. IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE)
e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 12, Issue 5 Ver. IV (Sep. - Oct. 2015), PP 82-91
www.iosrjournals.org
DOI: 10.9790/1684-12548291 www.iosrjournals.org 82 | Page
Selection of Spring Material Using PROMETHEE Method
Animesh Das1
, Awinash kumar2
1
(Department of Mechanical Engineering, Bengal Institute of Technology and Management, India)
2
(Department of Mechanical Engineering, Bengal Institute of Technology and Management, India)
Abstract: Like most other fundamental mechanical components which form the basis of many mechanical
systems, springs have existed since the Bronze Age for storage or release of energy, absorption or utilization of
vibration, relaxation or absorption of impact force and when unloaded, return to the original position or to the
original shape. Quality, service requirement, performance as well as durability of springs greatly depend on the
quality of materials used and manufacturing processes. So, spring material and its quality can normally be
taken into consideration and consequently, material selection plays an important role during designing of a
spring for a particular application. Common spring materials include stainless steel, alloy steels, carbon steels,
non-ferrous materials and some super-alloys which exist in the market with preparatory designations and
nomenclature. Each spring material has diverse compositions, individual properties and also for a particular
type of spring, more than one feasible alternative spring materials may be available in the market. To avoid
these complex conditions and consequently achieving the optimal spring design, it is exceptionally crucial to
select the most suitable material with the desired properties for enhanced durability, low operational and
manufacturing cost, and better performance of the spring. This paper considers a list of seven spring material
alternatives whose performance is evaluated based on eight selection criteria. An integrated preference ranking
organization method for enrichment evaluation (PROMETHEE II) and graphical analysis for interactive
assistance (GAIA) technique is applied to solve this spring material selection problem, and a full ranking of the
spring material alternatives with suitable graphical displays is presented. Chrome silicon alloy steel (ASTM A
401) is the best spring material, followed by high carbon steel (ASTM A 228) and Inconel 600. Monel K500 is
the worst chosen spring material.
Keywords : PROMETHEE Method, Rockwell Hardness, spring, Tensile Strength, Modulus of Elasticity,
I. INTRODUCTION
A coiled metal device that is able to store mechanical energy. It is an elastic object. A spring is a device
that changes its shape in response to an external force, returning to its original shape when the force is removed.
The energy expended in deforming the spring is stored in it and can be recovered when the spring returns to its
original shape. Generally, the amount of the shape change is directly related to the amount of force exerted. If
too large a force is applied, however, the spring will permanently deform and never return to its original shape.
There are several types of springs. One of the most common consists of wire wound into a cylindrical
or conical shape. An extension spring is a coiled spring whose coils normally touch each other; as a force is
applied to stretch the spring, the coils separate. In contrast, a compression spring is a coiled spring with space
between successive coils; when a force is applied to shorten the spring, the coils are pushed closer together. A
third type of coiled spring, called a torsion spring, is designed so the applied force twists the coil into a tighter
spiral. Common examples of torsion springs are found in clipboards and butterfly hair clips. Still another
variation of coiled springs is the watch spring, which is coiled into a flat spiral rather than a cylinder or cone.
One end of the spring is at the center of the spiral, and the other is at its outer edge. Some springs are fashioned
without coils. The most common example is the leaf spring, which is shaped like a shallow arch; it is commonly
used for automobile suspension systems. Another type is a disc spring, a washer-like device that is shaped like a
truncated cone. Open-core cylinders of solid, elastic material can also act as springs. Non-coil springs generally
function as compression springs.
Very simple, non-coil springs have been used throughout history. Even a resilient tree branch can be
used as a spring. More sophisticated spring devices date to the Bronze Age, when eyebrow tweezers were
common in several cultures. During the third century B.C., Greek engineer Ctesibius of Alexandria developed a
process for making "springy bronze" by increasing the proportion of tin in the copper alloy, casting the part, and
hardening it with hammer blows. He attempted to use a combination of leaf springs to operate a military
catapult, but they were not powerful enough. During the second century B.C., Philo of Byzantium, another
catapult engineer, built a similar device, apparently with some success. Padlocks were widely used in the ancient
Roman Empire, and at least one type used bowed metal leaves to keep the devices closed until the leaves were
compressed with keys.
2. Selection of Spring Material Using PROMETHEE Method
DOI: 10.9790/1684-12548291 www.iosrjournals.org 83 | Page
The next significant development in the history of springs came in the middle Ages. A power saw
devised by Villard de Honnecourt about 1250 used a water wheel to push the saw blade in one direction,
simultaneously bending a pole; as the pole returned to its unbent state; it pulled the saw blade in the opposite
direction.
In the eighteenth century, the Industrial Revolution spurred the development of mass-production
techniques for making springs. During the 1780s, British locksmith Joseph Bramah used a spring winding
machine in his factory. Apparently an adaptation of a lathe, the machine carried a reel of wire in place of a
cutting head. Wire from the reel was wrapped around a rod secured in the lathe. The speed of the lead screw,
which carried the reel parallel to the spinning rod, could be adjusted to vary the spacing of the spring's coils.
Common examples of current spring usage range from tiny coils that support keys on cellular phone touchpad to
enormous coils that support entire buildings and protect them from earthquake vibration.
Steel alloys are the most commonly used spring materials. The most popular alloys include high-carbon
(such as the music wire used for guitar strings), oil-tempered low-carbon, chrome silicon, chrome vanadium,
and stainless steel. Other metals that are sometimes used to make springs are beryllium copper alloy, phosphor
bronze, and titanium. Rubber or urethane may be used for cylindrical, non-coil springs. Ceramic material has
been developed for coiled springs in very high-temperature environments. One-directional glass fiber composite
materials are being tested for possible use in springs.
Various mathematical equations have been developed to describe the properties of springs, based on
such factors as wire composition and size, spring coil diameter, the number of coils, and the amount of expected
external force. These equations have been incorporated into computer software to simplify the design process.
Depending on the design and required operating environment, any material can be used to construct a spring, so
long as the material has the required combination of rigidity and elasticity: technically, a wooden bow is a form
of spring. But which material is best to use when designing a compression, extension or torsion spring is the
primary challenges for the designer.
Selection of the most appropriate material for a spring device is one of the primary challenges often
faced by the designers. As spring devices are able to store large amount of power, it should have sufficient
strength so that they will not fail under static loading or dynamic loading during normal operating conditions.
While selecting materials for spring device various material properties like tensile strength, modulus of
elasticity, modulus in torsion, maximum operating temperature, hardness, density, cost etc. are to be taken into
consideration. The present study involves PROMETHEE method as mathematical tool to select the most
appropriate spring material from a given set of alternatives spring materials.
II. LITERATURE SURVEY
Thus to taken in well thought-out the provisions of the spring manufacturing industries, researcher have
paid unrelenting attention for searching appropriate materials for spring. Kaiser et al [1] reports on procedure
and preliminary research results of long-term fatigue tests up to a number of 109 cycles on shot peened helical
compression springs with two basic dimensions, made of three different spring materials (oil hardened and
tempered SiCr- and SiCrV-alloy steel). Their result shows that the various spring types in test exhibit different
fatigue properties and also different failure mechanisms in the VHCF regime. Pöllänen et al. [2] proposed
optimum design of the spring which minimize of wire volume, space restriction, desired spring rate, avoidance
of surging frequency and achieving reliably long fatigue life. Their result was verified by using full 3D solid
FEM analysis with MSC Nastran by which the stresses and also strains, deformations and natural frequencies
and modes are obtained. Prawoto et al. [3] discusses about automotive suspension coil springs, their
fundamental stress distribution, materials characteristic, manufacturing and common failures. An in depth
discussion on the parameters influencing the quality of coil springs is also presented. Berger and Kaiser [4]
reported that the results of very high cycle fatigue tests on helical compression springs which respond to
external compressive forces with torsional stresses. The results of these investigations can add an important
contribution to the experience of fatigue behavior in the very high cycle regime. Most investigations performed
on that field deal with specimens under tensile or rotating bending load. These springs tested were manufactured
of Si-Cr-alloyed valve spring wire with a wire diameter between 2 and 5 mm, shot-peened and preset. Compared
to the fatigue limits evaluated in fatigue tests on these springs up to 107 cycles substantial decreases in fatigue
strength are to be observed if the fatigue tests are continued up to 108 cycles or even more. It is obvious that
nucleation’s of fractures tending to occur below the surface, if fractures happen after more than 107 cycles.
Investigations of broken springs by scanning electron microscope show a typical appearance of fracture
initiation sites without non-metallic inclusions at the nucleation’s of fracture.
III. PROMETHEE METHOD
The first paragraph under each heading or subheading should be flush left, and subsequent paragraphs
should have a five-space indentation. A colon is inserted before an equation is presented, but there is no
3. Selection of Spring Material Using PROMETHEE Method
DOI: 10.9790/1684-12548291 www.iosrjournals.org 84 | Page
punctuation following the equation. All equations are numbered and referred to in the text solely by a number
enclosed in a round bracket (i.e., (3) reads as "equation 3"). Ensure that any miscellaneous numbering system
you use in your paper cannot be confused with a reference [4] or an equation (3) designation. (10)
The PROMETHEE I (partial ranking) and PROMETHEE II (complete ranking) were developed by J.P.
Brans [5] and presented for the first time in 1982 at a conference. A few years later J.P. Brans and B. Mareschal
developed PROMETHEE III (ranking based on intervals) and PROMETHEE IV (continuous case). In 1992 and
1994, J.P. Brans and B. Mareschal further suggested two nice extensions, PROMETHEE V (MCDA including
segmentation constraints) and PROMETHEE VI (representation of the human brain). A considerable number of
successful applications has been treated by the PROMETHEE methodology in various fields such as banking,
industrial location, manpower planning, water resources, investments, medicine, chemistry, health care, tourism,
ethics in OR, dynamic management etc. The success of the methodology is basically due to its mathematical
properties and to its simplicity.
Many multicriteria decision aid methods have been proposed by researcher to deal the optimization
problem. All the method start from the same evaluation table, but they vary according to the additional
information they request. The PROMETHEE methods require very clear additional information that is easily
obtained and understood by both decision makers and analysts.
The purpose of all multicriteria methods is to enrich the dominance graph, i.e. to reduce the number of
incomparabilities(R). When a utility function is built, the multicriteria problem is reduced to a single criterion
problem for which an optimal solution exists. This seems exaggerated because it relies on quite strong
assumptions and it completely transforms the structure of the decision problem. For this reason B. Roy proposed
to build outranking relations including only realistic enrichments of the dominance relation [6]. In that case, not
all the incomparabilities are withdrawn but the information is reliable. The PROMETHEE methods belong to
the class of outranking methods.
The PROMETHEE methods were designed to treat multicriteria problems, the additional information
requested to run PROMETHEE is particularly clear and understandable by both the analysts and the decision-
makers. It consists of information between the criteria; information within each criterion.
Table 1reveledthat the set {Wj= j, j=1,2,…,k} represents weights of relative importance of the different
criteria. These weights are non-negative numbers, independent from the measurement units of the criteria.
Table 1 Weight of relative importance
g1(.) g2(.) …. gj(.) …. gk(.)
W1 W2 …. Wj …. Wk
The higher the weight, the more important the criterion. There is no objection to consider normed
weights, so that:
(1)
PROMETHEE is not allocating an intrinsic absolute utility to each alternative, neither globally, nor on
each criterion. The preference structure of PROMETHEE is based on pair-wise comparisons. In this case the
deviation between the evaluations of two alternatives on a particular criterion is considered. For small
deviations, the decision-maker will allocate a small preference to the best alternative and even possibly no
preference if decision maker considered that this deviation is negligible. The larger the deviation, the larger the
preference. There is no objection to consider that these preferences are real numbers varying between 0 and 1.
This means that for each criterion the decision-maker has in mind a function
(2)
Where:
(3)
and for which:
(4)
In case of a criterion to be maximized, this function is giving the preference of ‘a’ over ‘b’ for observed
deviations between their evaluations on criterion .The preferences equal 0 when the deviations are
negative.
The following property holds:
(5)
4. Selection of Spring Material Using PROMETHEE Method
DOI: 10.9790/1684-12548291 www.iosrjournals.org 85 | Page
For criteria to be minimized, the preference function should be reversed or alternatively given by:
(6)
Now called the pair the generalized criterion associated to criterion such a
generalized criterion has to be defined for each criterion. In order to facilitate the identification six
types of particular preference functions have been proposed.
Type 1: Usual criterion
P(d) = (7)
Type 2: U-shape criterion
P(d) = (8)
where ‘q’ is the fix parameter
Type 3: V-shape criterion
P(d) = (9)
where ‘p’ is the fix parameter
Type 4: Level criterion
P(d)= (10)
where ‘p,q’ are the fix parameters
Type 5: V-shape with indifference
P(d) = (11)
Where ‘p,q’ are the fix parameters
Type 6: Gaussian criterion
P(d)= (12)
where‘s’ is the fix parameter
In each case 0, 1 or 2 parameters have to be defined, their significance is clear, ‘q’ is a threshold or
indifference; ‘p’ is a threshold of strict preference; ‘s’ is an intermediate value between and ‘p’ and ‘q’.
The indifference threshold is the largest deviation which is considered as negligible by the decision
maker, while the preference threshold is the smallest deviation which is considered as sufficient to generate a
full preference. The identification of a generalized criterion is then limited to the selection of the appropriate
parameters. It is an easy task.
In case of type 5 (V-shape with indifference) a threshold of indifference ‘q’ and a threshold of strict
preference ‘p’ have to be selected. Gaussian criterion (type 6) the preference function remains increasing for all
deviations and has no discontinuities, neither in its shape, nor in its derivatives. A parameter has to be selected;
it defines the inflection point of the preference function. It is then recommend to determine first a ‘q’ and a ‘p’
5. Selection of Spring Material Using PROMETHEE Method
DOI: 10.9790/1684-12548291 www.iosrjournals.org 86 | Page
and to fix in between ‘s’. If‘s’ is close to the ‘q’ preferences will be reinforced for small deviation, while close
to ‘p’ they will be softened.
As soon as the evaluation table is given, and the weights wj and the generalized criteria
} are defined for i=1,2,…,n; j=1,2,….,k, the PROMETHEE procedure can be applied.
The PROMETHEE I procedure is based on pair-wise comparisons [7]. Let us first define aggregated
preference indices and outranking flows.
Let, a, b Є A, and let:
(13)
is expressing with which degree ‘a’ is preferred to ‘b’ over all the criteria and
how ‘b’ is preferred ‘a’. In most of the cases there are criteria for which ‘a’ is better than ‘b’, and criteria for
which ‘b’ is better than ‘a’, consequently and are usually positive.
The following properties holds for all (a, b) Є A.
(14)
It is clear that:
(15)
Each alternative ‘a’ is facing (n-1) other alternatives in A. Let us define the two following outranking
flows:
The positive out ranking flow:
(16)
The negative out ranking flow:
(17)
The positive outranking flow expresses how an alternative ‘a’ is outranking all the others. It is its
power, its outranking character. The higher the better the alternative. The negative outranking flow
expresses how an alternative ‘a’ is outranked by all the others. It is its weakness, its outranked character. The
lower the better the alternative.
The PROMETHEE I partial ranking ( is obtained from the positive and the negative
outranking flows. Both flows do not usually induce the same rankings. PROMETHEE I is their intersection.
(18)
Where respectively stand for preference, indifference and incomparability.
When a higher power of ‘a’ is associated to a lower weakness of ‘a’ with regard to ‘b’. The
information of both outranking flows is consistent and may therefore be considered as sure. When both
positive and negative flows are equal. When a higher power of one alternative is associated to a lower
weakness of the other. This often happens when ‘a’ is good on a set of criteria on which ‘b’ is weak and
reversely ‘b’ is good on some other criteria on which ‘a’ is weak. In such a case the information provided by
both flows is not consistent. It seems then reasonable to be careful and to consider both alternatives as
6. Selection of Spring Material Using PROMETHEE Method
DOI: 10.9790/1684-12548291 www.iosrjournals.org 87 | Page
incomparable. The PROMETHEE I ranking is prudent: it will not decide which action is best in such cases. It is
up to the decision-maker to take his responsibility.
Promethee II is a well-established decision support system [8, 9] is used to rank the different options
based on selected criteria. In this paper, the PROMETHEE II method is employed to obtain the full ranking of
the alternative locations for a given industrial application.
The procedural steps as involved in PROMETHEE II method are enlisted as below [5, 10]
Step 1: Normalize the decision matrix using the following equation:
(i =1,2,…,n : j = 1,2,..,m) (19)
Where is the performance measure of ith
alternative with respect to jth
criterion.
For non-beneficial criteria, Eqn. (12) can be rewritten as follows:
(20)
Step 2: Calculate the evaluative differences of ith
alternative with respect to other alternatives. This step
involves the calculation of differences in criteria values between different alternatives pair-wise.
Step 3: Calculate the preference function .
There are mainly six types of generalized preference functions as proposed by Brans and Mareschal
[10]. But these preference functions require the definition of some preferential parameters, such as the
preference and indifference thresholds. However, in real time applications, it may be difficult for the decision
maker to specify which specific form of preference function is suitable for each criterion and also to determine
the parameters involved. To avoid this problem, the following simplified preference function is adopted here:
(21)
(22)
Step 4: Calculate the aggregated preference function taking into account the criteria weights.
Aggregated preference function, (23)
Where Wj is the relative importance (weight) of jth
criterion.
Step 5: Determine the leaving and entering outranking flows as follows:
Leaving (or positive) flow for
th
i alternative, (24)
Entering (or negative) flow for
th
i alternative, (25)
Where n is the number of alternatives.
Here, each alternative faces (n – 1) number of other alternatives. The leaving flow expresses how much
an alternative dominates the other alternatives, while the entering flow denotes how much an alternative is
dominated by the other alternatives. Based on these outranking flows, the PROMETHEE I method can provide a
partial preorder of the alternatives, whereas, the PROMETHEE II method can give the complete preorder by
using a net flow, though it loses much information of preference relations.
Step 6: Calculate the net outranking flow for each alternative.
(26)
Step 7: Determine the ranking of all the considered alternatives depending on the values of The
higher value of the better is the alternative. Thus, the best alternative is the one having the highest
value.
The PROMETHEE method is an interactive multi-criteria decision-making approach designed to
handle quantitative as well as qualitative criteria with discrete alternatives. In this method, pair-wise comparison
of the alternatives is performed to compute a preference function for each criterion. Based on this preference
function, a preference index for alternative i over i is determined. This preference index is the measure to
support the hypothesis that alternative i is preferred to i . The PROMETHEE method has significant
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advantages over the other MCDM approaches, e.g. multi-attribute utility theory (MAUT) and AHP. The
PROMETHEE method can classify the alternatives which are difficult to be compared because of a trade-off
relation of evaluation standards as non-comparable alternatives. It is quite different from AHP in that there is no
need to perform a pair-wise comparison again when comparative alternatives are added or deleted.
IV. SPRING MATERIAL SELECTION
Frequently, the operating environment is the single most important consideration for proper spring
material selection. For successful application, material must be compatible with the environment and withstand
effects of temperature and corrosion without an excessive loss in spring performance. Corrosion and elevated
temperatures decrease spring reliability. The effect of temperature on spring materials is predictable.
When specifying a compression or a tension spring, designers will be aware of the forces and degree of
accuracy required, together with the operational conditions. From this information, designers must select a
material from which a spring can be made. A maximum permissible stress can then be determined, which,
together with the load requirements, will enable suitable dimensions to be selected.
Hence, in order to apply PROMETHEE II method to solve the spring material selection problem and
prove its potentiality and universal applicability for dealing with this type of complex decision-making problem,
the corresponding decision matrix of Table 1 is developed. This decision-matrix comprising of seven spring
material alternative and eight important selection criteria. Most of the criteria values of Table 1 are taken from
handbook/ website [11,12]. The details of these eight selection criteria are given in Table 2.
This decision matrix consists of seven spring materials and eight pivotal selection criteria. All the
criteria values of Table 1 are accumulated from different handbooks. The details of these eight selection criteria
are given in Table 2.
Tensile strength measures the force required to pull something such as rope, wire, or a structural beam
to the point where it breaks. The tensile strength of a material is the maximum amount of tensile stress that it
can take before failure. An elastic modulus, or modulus of elasticity, is the mathematical description of an object
or substance's tendency to be deformed elastically (i.e., non-permanently) when a force is applied to it. The
elastic modulus of an object is defined as the slope of its stress–strain curve in the elastic deformation region. As
such, a stiffer material will have a higher elastic modulus. It defines the ratio of stress and strain. It is a measure
of an object's ability to resist torsion. It is required to calculate the twist of an object subjected to a torque. It is
analogous to the area moment of inertia, which characterizes an object's ability to resist bending and is required
to calculate displacement. The larger the modulus in torsion, the less the beam will twist, when subjected to a
given torque. In between which temperature the materials can work without any kind of change of stage and can
give the maximum efficiency. Larger the value of Maximum operating temperature the material can withstand
that much temperature. Hardness is the measure of how resistant solid matter is to various kinds of permanent
shape change when a force is applied. The Rockwell scale is a hardness scale based on the indentation hardness
of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter
under a large load compared to the penetration made by a preload. The mass density or density of a material is
defined as its mass per unit volume. Density is a physical property of matter, as each element and compound has
a unique density associated with it. Density defined in a qualitative manner as the measure of the relative
"heaviness" of objects with a constant volume. The cost of a spring material indicates its current market price
which greatly influences the final spring cost. It is expressed in terms of the price value per unit weight of the
spring material. So, its cost should be as low as possible and is taken as a non-beneficial criterion.
Table 3 shows an exhaustive list of the seven alternative supercritical boiler materials. The composition
of high carbon steel ASTMA 228 is C 0.70 - 1.00% and Mn 0.20 – 0.60%. Music Wire ASTMA 228 are the
most commonly used of all springs materials. These materials in preference to others because that are least
expensive, readily available, easily worked, and most popular. These materials are not satisfactory for high or
low temperatures or for shock or impact loading. This high quality high-carbon spring wire is the most common
and readily available today. You might say that music wire will give you the biggest bang for your buck. This
material is widely used for helical compression, extension and torsion springs in a wide range of applications,
especially in the finer wire diameters. Known for its high tensile strength, high elastic limit, and music wire can
withstand high stresses under repeated loadings, and will continue to perform well under many normal cyclic
applications. The composition of Beryllium Copper ASTM B 197 is Cu 98.0% and Be 2.0%.Copper-base alloys
are important spring materials because of their good electrical properties combined with their excellent
resistance to corrosion. Although these materials are more expensive than the high-carbon and the alloy steels,
they nevertheless are frequently used in electrical components and in subzero temperatures. All copper-base
alloys are drawn to the American wire gage (same as Brown & Sharpe gage) and are nonmagnetic. The
composition of Monel K 500 - QQ-N-286 is Ni 63.0%, Cu 29.5%, Al 2.7%, Ti 0.6%, C 0.18%, Fe 2.0%, Mn
1.5%, Si 0.50%, S 0.010%. Alloy K-500 is a nickel-copper alloy, precipitation hardenable through additions of
aluminum and titanium. This alloy retains the excellent corrosion resistant characteristics of 400 and has
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enhanced strength and hardness after precipitation hardening when compared with 400. Alloy K-500 has
approximately three (3) times the yield strength and double the tensile strength when compared with 400. K-500
can be further strengthened by cold working before the precipitation hardening. Excellent mechanical properties
from sub-zero temperatures up to about 480C. Corrosion resistance in an extensive range of marine and
chemical environments. The composition of Chrome Silicon ASTM A 401 is C 0.51 - 0.59%, Cr 0.60 - 0.80%,
Si 1.20 - 1.60%.The alloy spring steels have a definite place in the field of spring materials, particularly for
conditions involving high stress and for applications where shock or impact loading occurs. Alloy spring steels
also can withstand higher and lower temperatures than the high-carbon steels and are obtainable in either the
annealed or pre tempered conditions. These materials are not regularly stocked in a wide variety of sizes. The
composition of AISI 302/304 Stainless Steel is Cr 17.0 - 19.0% and Ni 8.0 - 10.0%. The use of stainless spring
steels has increased considerably in recent years. Several new compositions are now available to withstand
corrosion. All of these materials can be used for high temperatures up to 650°F.The composition of Inconel 600
- QQ-W-390 is Ni 76.0%, Cr 15.8% and Fe 7.2%. Nickel-based alloys are especially useful spring materials to
combat corrosion and to withstand both elevated and below-zero temperature application. Their nonmagnetic
characteristic is important for such devices as gyroscopes, chronoscopes, and indicating instruments. These
materials have high electrical resistance and should not be used for conductors of electrical current. The
composition of Nickel Alloy is C 0.08,Mn 2,Al 0.35,Ni 24-27,P 0.025, S 0.025, Cr 13.5-16, Si 1,Mo 1-1.5, Ti
1.9-2.35,Vd 0.1-0.5,B 0.003-0.01,Fe balance. Type A286 alloy content is similar in chromium, nickel, and
molybdenum to some of the austenitic stainless steels. Consequently, A286 alloy possesses a level of aqueous
corrosion resistance comparable to that of the austenitic stainless steels. In elevated temperature service, the
level of corrosion resistance to atmospheres such as those encountered in jet engine applications is excellent to
at least 1300°F (704°C). Oxidation resistance is high for continuous service up to 1500°F (816°C) and
intermittent service up to 1800°F (982°C).
V. CALCULATION
For solving this spring material selection problem using PROMETHEE II method, the decision matrix
of Table1 is taken. Considering both beneficial and non-beneficial criteria, the decision matrix, as shown in
Table 1, is normalized using Equation (19) and (20) is given in Table 5. The leaving (positive) and the entering
(negative) flows for different spring material alternatives are now computed using Equations (24) and (25),
respectively, and are shown in Table 6. The net outranking flow values for the spring material alternatives are
calculated using Equation (26) and is given in Table 7 Now, after arranging the spring material alternative in
descending order of their net outranking flow values, ranking of different spring material alternatives are also
given in Table 7. It is observed that Chrome Silicon Alloy Steel (ASTM A 401) is the most appropriate choice
as a spring material. High Carbon Steel (ASTM A 228) and Inconel 600 may also be used as a spring materials
because of these materials obtain second and third ranks. Monel K500 is a worst material for spring.
VI. LIST OF TABLES
Table 1 Decision matrix for spring material selection problem
Alternatives B1 B2 B3 B4 B5 B6 B7 B8
A1 2168.5 207 45 79.3 121 50.5 7.85 35
A2 1310 128 45 48.3 204 38.5 8.26 33
A3 1241 179 40 65.5 288 29 8.44 55
A4 1844.5 207 45 79.3 245 51.5 7.85 30
A5 1551.5 193 35 69 288 40 7.92 15
A6 1379 214 40 75.8 371 40 8.47 45
A7 1241 200 35 71.7 510 38.5 7.92 32
Table 2 Criteria for spring material selection
Properties of Spring Material Symbols
Tensile Strength (MPa) B1
Modulus of Elasticity (GPa) B2
Design Stress percentage Min. Tensile (%) B3
Modulus in Torsion (GPa) B4
Max. Operating Temp (˚C) B5
Rockwell Hardness (HRC) B6
Density (gm/cc) B7
Material Cost ($/Kg.) B8
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Table 3 Spring materials
Materials Symbols
High Carbon Steel (ASTM A 228) A1
Beryllium Copper Alloy (ASTM B 197) A2
Monel K500 A3
Chrome Silicon Alloy Steel (ASTM A 401) A4
Stainless Steel (AISI 304) A5
Inconel 600 A6
Nickel Alloy(ASTM A 286) A7
Table 4 Weights for different criteria.
Criteria B1 B2 B3 B4 B5 B6 B7 B8
Weight 0.7680 0.0679 0.0103 0.0203 0.1133 0.0105 0.0012 0.0086
Table 5 Normalized decision matrix for spring material selection problem
Alternatives
Materials B1 B2 B3 B4 B5 B6 B7 B8
A1
1.0000 0.9186 1.0000 1.0000 0.0000 0.9556 1.0000 0.5000
A2
0.0744 0.0000 1.0000 0.0000 0.2134 0.4222 0.3387 0.5500
A3
0.0000 0.5930 0.5000 0.5548 0.4293 0.0000 0.0484 0.0000
A4
0.6507 0.9186 1.0000 1.0000 0.3188 1.0000 1.0000 0.6250
A5
0.3348 0.7558 0.0000 0.6677 0.4293 0.4889 0.8871 1.0000
A6
0.1488 1.0000 0.5000 0.8871 0.6427 0.4889 0.0000 0.2500
A7
0.0000 0.8372 0.0000 0.7548 1.0000 0.4222 0.8871 0.5750
Table 6 Leaving and entering flows for different spring materials
Alternatives Leaving (Positive) flow Entering (Negative) flow
A1 0.4119 0.0128
A2 0.0683 0.4186
A3 0.0442 0.4622
A4 0.4385 0.0050
A5 0.1264 0.1754
A6 0.1146 0.1211
A7 0.1139 0.1800
Table 7 Net outranking flow values & corresponding ranking for different spring material
Alternatives Net outranking flow Ranking
A1 2.3992 2
A2 1.6497 6
A3 1.5821 7
A4 2.4335 1
A5 1.9510 4
A6 1.9934 3
A7 1.9339 5
VII. CONCLUSION
As of the literature survey, it is observed that the past researches have took the help of different
experimental techniques for mechanical properties characterization to aid the spring designer select the best
spring material for particular type of spring, there is a fervent requirement for an efficient mathematical
approach to solve the spring material selection problem. In this paper, PROMETHEE II method is applied to
select the best material for a given spring. The observed results are accurately in accordance with the expected
choices. Hence, in many real times decision-making situations, where the evaluation is done using quantitative
and qualitative data, this method can be efficiently used to obtain more precise results. This method can be
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extended to support and increase the efficiency of the decision-making process related to selection of materials
for other engineering applications.
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