Modal analysis determines the natural vibration characteristics of a structure. Natural frequency depends on mass, stiffness, and boundary conditions, and is important to understand possible resonance. Resonance occurs when natural frequency coincides with excitation frequency, and can cause excessive deformation. The document provides an example modal analysis of a simply supported aluminum plate, calculating its natural frequencies. Finite element analysis is used to model the system and structures are substantiated to have sufficient margin of safety under limit loads.
The document summarizes concepts related to fatigue in welded steel structures. It discusses the mechanism of fatigue failure, factors influencing fatigue behavior, effects of fatigue loading on structural members and weld connections, fatigue analysis methods including the S-N approach and fracture mechanics approach, Indian standard practices, techniques to improve fatigue strength, and conclusions.
IRJET- Nonlinear Transient Vibration Analysis of Mounting Superstructure for ...IRJET Journal
1) The document describes a nonlinear transient vibration analysis of a mounting superstructure designed to isolate vibration sensitive cargo during road transportation.
2) Wire rope isolators are selected to connect the mounting frame to the vehicle base frame in order to dissipate vibration energy from road shocks and impacts.
3) A nonlinear transient analysis is conducted to investigate the shock response of the designed mounting superstructure when subjected to road generated shock pulses, as the isolators exhibit nonlinear stiffness.
This document discusses mechanical properties that can be determined from tensile and shear tests. It defines key terms like stress, strain, elastic modulus, yield strength, and tensile strength. A typical stress-strain curve is shown and each region is explained. The elastic portion is linear up to the yield point, then the plastic region involves necking and strain hardening until ultimate failure. True stress and strain account for changes in cross-sectional area during deformation. The document also compares properties like ductility and toughness between different materials.
Given:
Stresses:
i) 350 N/mm2 for 85% of time
ii) 500 N/mm2 for 3% of time
iii) 400 N/mm2 for 12% of remaining time
Material: Plain carbon steel 50C
Using Miner's rule:
For stress i)
N1/Nf1 = 0.85
Where, N1 is no. of cycles component can withstand at stress 350 N/mm2
Nf1 is no. of cycles to failure at stress 350 N/mm2
Similarly, for other stresses:
N2/Nf2 = 0.03
N3/Nf3 = 0.12
Equ
The document discusses an Instron machine, which is a versatile instrument used to measure load from 2 grams to 100 kgs using a strain gauge principle. It consists of a load cell containing metal beams with strain gauges that measure the resistance change when a load is applied. This allows the machine to generate a load-elongation curve on a chart. The Instron machine can test properties of yarns, cords, fibers and other materials under tension, and has applications in measuring tensile, flexural, friction and tear properties. It operates over a wide range of speeds and loads with interchangeable load cells and grips.
The document summarizes the analysis and design of trusses for a Jordanian synchrotron roof structure. It describes the project, loads on the structure, and the analysis process. The trusses were analyzed using structural analysis software. The design process for tension and compression members is then outlined, including selecting sections, checking capacities and slenderness ratios. Examples of designing a compression member and tension member are provided. Finally, the document discusses the procedure for designing truss connections, including determining the number and spacing of bolts.
IRJET - An Investigation of Stresses Induced in Curved Beams using MATLAB...IRJET Journal
This document investigates stresses induced in curved beams using MATLAB and finite element analysis (FEA). It analyzes three cross-sectional shapes - trapezoidal, circular, and elliptical - for a crane hook subjected to a 100kN load. MATLAB code is used to calculate stresses in each section, finding the trapezoidal section experiences the lowest maximum stress of 171 MPa. FEA software ANSYS is also used to model each section and determine von Mises stresses, validating the results. The trapezoidal section is identified as optimal for withstanding the load with minimum induced stress.
The document discusses stress concentration and fatigue failure in machine elements. It defines stress concentration as the localization of high stresses due to irregularities or abrupt changes in cross-section. Stress concentration can be reduced by avoiding sharp changes in cross-section and providing fillets and chamfers. Fatigue failure occurs when fluctuating stresses cause cracks over numerous load cycles. The endurance limit is the maximum stress amplitude that causes failure after an infinite number of cycles. Factors like stress concentration, surface finish, size, and mean stress affect the endurance limit. Designs should minimize stress raisers and protect against corrosion to prevent fatigue failures.
The document summarizes concepts related to fatigue in welded steel structures. It discusses the mechanism of fatigue failure, factors influencing fatigue behavior, effects of fatigue loading on structural members and weld connections, fatigue analysis methods including the S-N approach and fracture mechanics approach, Indian standard practices, techniques to improve fatigue strength, and conclusions.
IRJET- Nonlinear Transient Vibration Analysis of Mounting Superstructure for ...IRJET Journal
1) The document describes a nonlinear transient vibration analysis of a mounting superstructure designed to isolate vibration sensitive cargo during road transportation.
2) Wire rope isolators are selected to connect the mounting frame to the vehicle base frame in order to dissipate vibration energy from road shocks and impacts.
3) A nonlinear transient analysis is conducted to investigate the shock response of the designed mounting superstructure when subjected to road generated shock pulses, as the isolators exhibit nonlinear stiffness.
This document discusses mechanical properties that can be determined from tensile and shear tests. It defines key terms like stress, strain, elastic modulus, yield strength, and tensile strength. A typical stress-strain curve is shown and each region is explained. The elastic portion is linear up to the yield point, then the plastic region involves necking and strain hardening until ultimate failure. True stress and strain account for changes in cross-sectional area during deformation. The document also compares properties like ductility and toughness between different materials.
Given:
Stresses:
i) 350 N/mm2 for 85% of time
ii) 500 N/mm2 for 3% of time
iii) 400 N/mm2 for 12% of remaining time
Material: Plain carbon steel 50C
Using Miner's rule:
For stress i)
N1/Nf1 = 0.85
Where, N1 is no. of cycles component can withstand at stress 350 N/mm2
Nf1 is no. of cycles to failure at stress 350 N/mm2
Similarly, for other stresses:
N2/Nf2 = 0.03
N3/Nf3 = 0.12
Equ
The document discusses an Instron machine, which is a versatile instrument used to measure load from 2 grams to 100 kgs using a strain gauge principle. It consists of a load cell containing metal beams with strain gauges that measure the resistance change when a load is applied. This allows the machine to generate a load-elongation curve on a chart. The Instron machine can test properties of yarns, cords, fibers and other materials under tension, and has applications in measuring tensile, flexural, friction and tear properties. It operates over a wide range of speeds and loads with interchangeable load cells and grips.
The document summarizes the analysis and design of trusses for a Jordanian synchrotron roof structure. It describes the project, loads on the structure, and the analysis process. The trusses were analyzed using structural analysis software. The design process for tension and compression members is then outlined, including selecting sections, checking capacities and slenderness ratios. Examples of designing a compression member and tension member are provided. Finally, the document discusses the procedure for designing truss connections, including determining the number and spacing of bolts.
IRJET - An Investigation of Stresses Induced in Curved Beams using MATLAB...IRJET Journal
This document investigates stresses induced in curved beams using MATLAB and finite element analysis (FEA). It analyzes three cross-sectional shapes - trapezoidal, circular, and elliptical - for a crane hook subjected to a 100kN load. MATLAB code is used to calculate stresses in each section, finding the trapezoidal section experiences the lowest maximum stress of 171 MPa. FEA software ANSYS is also used to model each section and determine von Mises stresses, validating the results. The trapezoidal section is identified as optimal for withstanding the load with minimum induced stress.
The document discusses stress concentration and fatigue failure in machine elements. It defines stress concentration as the localization of high stresses due to irregularities or abrupt changes in cross-section. Stress concentration can be reduced by avoiding sharp changes in cross-section and providing fillets and chamfers. Fatigue failure occurs when fluctuating stresses cause cracks over numerous load cycles. The endurance limit is the maximum stress amplitude that causes failure after an infinite number of cycles. Factors like stress concentration, surface finish, size, and mean stress affect the endurance limit. Designs should minimize stress raisers and protect against corrosion to prevent fatigue failures.
Analysing and Comparing the Behaviours of Cylindrical Fatigue Specimens Made ...IRJET Journal
This document analyzes and compares the behaviors of cylindrical fatigue specimens made of nickel-titanium shape memory alloy and steel using finite element analysis in Abaqus. The modal frequencies and deformations were analyzed for the first 20 modes of each material. For both materials, higher order flexions occurred at higher frequencies. Tensile stress was highest in the gauge section and highest for steel due to its higher Young's modulus. The nickel-titanium alloy specimen had a lower maximum frequency, energy, and tensile stress compared to steel. Shape memory alloys are implemented in structures for vibration control and energy dissipation during earthquakes.
This document provides information on selecting fastener materials and their mechanical properties. It discusses the most common material, carbon steel, and its various grades. It also covers stainless steel types including austenitic, martensitic, and ferritic, and provides examples of common grades for each type. Additional materials discussed include alloy steels and precipitation hardening stainless steel. The document aims to provide basic knowledge on fastener materials to help with evaluating the right material for an application.
Review of shaft failure in Coil Car AssemblyIRJET Journal
This document summarizes a study on failures of shafts in coil car assemblies. The researchers investigated a failed coil car shaft and found that reversed bending fatigue caused it to fracture, occasionally due to misalignment. They calculated loads on the existing shaft theoretically and analytically and found the stresses exceeded permissible levels, indicating it was prone to failure. To improve shaft design, they examined increasing diameter and using fillets/chamfers to disperse stresses. A literature review showed other shaft failures were due to low radius of curvature, incorrect chamfer size increasing stress concentration, and vibrations from imbalance.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
The document discusses determining the fatigue behavior of engine damper cap screw bolts. It describes testing the bolts to determine their ultimate tensile strength, hardness, preload, and fatigue strength. Samples of the bolts were tested under various alternating loads with a constant mean load to generate an S-N curve showing their fatigue life. It was found that fatigue failure occurred in the threads due to high stress concentration, and the average preload of the bolts was determined to be 40,000 lbs using ultrasonic measurement.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
The document discusses determining the fatigue behavior of engine damper cap screw bolts. It begins with an abstract that outlines testing cap screw bolts under different alternating loads to determine their fatigue strength using the S-N method. It then provides background on issues like insufficient bolt preload leading to failure. The document describes testing the mechanical properties of damper cap screw bolts, including hardness, ultimate tensile strength from tension tests, and evaluating their chemical composition. It aims to determine the cap screw bolts' fatigue strength and failure locations under fatigue testing.
The document discusses design considerations for machine elements subjected to fluctuating loads. It covers topics such as stress concentration, fatigue failure, endurance limit, factors affecting fatigue strength, and methods to reduce stress concentration and improve fatigue life. Stress concentration occurs due to discontinuities and can be reduced by avoiding abrupt changes in cross-section and providing fillets. Fatigue failure is caused by fluctuating stresses and depends on factors like the number of cycles and mean stress. The endurance limit is the maximum stress amplitude a material can withstand without failure under completely reversed loading. Surface finish, size, and mean stress affect the endurance limit.
The document discusses stress concentration and fatigue failure in machine elements. It defines stress concentration as irregular stress distribution caused by abrupt changes in cross-section shape. Stress concentration factors are introduced to quantify the maximum stress compared to nominal stress. The document also discusses endurance limit and fatigue strength testing methods. Factors that affect fatigue strength like material properties, surface finish, size and temperature are summarized. Methods to evaluate and reduce stress concentration in designs are provided.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This document provides an overview of basic design considerations for machine components. It discusses general design procedures and considerations, types of loads, stress-strain diagrams, types of stresses including tensile, compressive, shear, crushing, bearing, torsional, and bending stresses. It also covers concepts related to stress concentration, creep, fatigue, endurance limit, factor of safety, and theories of failure under static loads. Standard classifications and designations of various steel and alloy types are also presented.
Deflections in PT elements pt structure for all pt slabs in civil industry.pdfvijayvijay327286
The document discusses factors that influence deflections in prestressed concrete members and methods for predicting deflections. It covers:
- Short term deflections of unracked members which can be estimated using Mohr's theorem.
- How the tendon profile affects deflections, providing formulas for straight, trapezoidal, parabolic, and other tendon types.
- Downward deflections due to self-weight and imposed loads that can be calculated using formulas provided.
- Estimation of long-term deflections accounting for creep and shrinkage effects, discussing various methods like those of Busemann, McHenry, and Neville.
The document provides information about aircraft structures and structural analysis. It defines primary and secondary aircraft structures, and monocoque and semi-monocoque constructions. It describes the functions of different structural elements like the skin, ribs, spars, and stringers. It discusses simplifications made in structural analysis, including lumping longitudinal members and assuming webs only experience shear stresses. It also covers topics like unsymmetric bending, shear flow, shear centers, and torsion of thin-walled closed sections.
- Fatigue analysis aims to estimate the life of aircraft components under fluctuating cyclic loads.
- The stress-life (S-N) method relates the cyclic stress range to the number of cycles to failure and is commonly used. S-N curves are generated from testing and provide fatigue strength values.
- Stress concentrations around holes, notches, joints and other discontinuities significantly reduce the fatigue life of components and must be accounted for using stress concentration factors.
This document provides a review of limit load solutions for structural components containing defects. It summarizes existing limit load solutions for plates, cylinders, spheres, pipe bends, and shell/nozzle intersections with various defect geometries under different loading conditions. The solutions are useful for failure assessment methods that utilize the limit load or reference stress concept. Experimental verification of some solutions is also discussed, along with factors such as material and geometric hardening effects.
The document discusses different types of strain gauges used to measure strain. It describes how strain gauges work by changing electrical resistance proportionally to strain. Common types include metallic wire or foil grids bonded to a backing material. Materials like constantan/advance are often used due to properties like self-temperature compensation and linear strain sensitivity. Unbounded wire strain gauges consist of tensioned wires connected to a Wheatstone bridge circuit to measure strain through changes in electrical resistance. Strain gauges are widely applied to experimental stress analysis of structures, machines, vehicles and more.
IRJET- Forced Damped Vibration Analysis of Optimized Cantilever Beam using Di...IRJET Journal
This document summarizes a study on analyzing the forced damped vibration of an optimized cantilever beam using different methods. The study aims to identify a suitable material for manufacturing an engine casing by considering parameters like material, weight, damping coefficient, spring stiffness, and natural frequency. Using the Taguchi method and regression analysis, aluminum is identified as the optimal material. The natural frequency is then evaluated using theoretical, experimental (FFT analyzer), and simulation (ANSYS) methods. Time graphs and FFT readings from the experimental setup show peak frequencies that match the theoretical natural frequency of 5.36 Hz calculated using analytical methods.
The document discusses tensile strength and tensile testing. It defines tensile strength as the maximum stress a material can withstand under tension before necking and breaking. A tensile test measures how a material responds to tensile forces by recording the load and elongation of a test specimen. The results are displayed as a stress-strain curve which can show properties like yield strength, ultimate tensile strength, modulus of elasticity, and ductility measures.
The document discusses tensile strength and tensile testing. It defines tensile strength as the maximum stress a material can withstand under tension before necking and breaking. A tensile test measures how a material responds to tensile forces by recording the load and elongation of a test specimen. The results are used to determine various tensile properties including modulus of elasticity, yield strength, ultimate tensile strength, and measures of ductility. Hooke's law and concepts like strain, stress-strain curves, and necking are also explained in the context of understanding a material's tensile behavior.
Evaluation of Reduction in Compressive Strength of Singly Symmetric CFS Membe...IRJET Journal
This document presents a study evaluating the reduction in compressive strength of cold-formed steel lipped channel columns due to local buckling effects. A finite element analysis is conducted to analyze the behavior of fixed-ended and pinned-ended columns under compression. The analysis shows that local buckling causes a shift in the effective centroid for pinned columns, introducing overall bending and reducing capacity by up to 39% compared to fixed-ended columns. A parametric study is performed to evaluate the effects of cross-section dimensions, material properties, and slenderness ratios on column strength. Results are also compared to several design methods to evaluate their accuracy in predicting the behavior and strength of cold-formed steel columns.
Lecture 1 Single Mode Loading Part A.docDylanONeill11
This document discusses single-mode loading conditions that will be covered in the class, including axial loading, direct shear, torsional loading, and beam bending. It provides examples and equations for calculating stresses and deformations for each loading condition. For axial loading of a rod, it shows how to calculate the load at yield and ultimate failure. For direct shear, it discusses shear area and provides examples. For torsional loading, it introduces the torsion formula and shows how to calculate shear stresses. It also discusses stress concentrations and provides an example problem calculating maximum shear stress in a lawnmower drive shaft.
Analysing and Comparing the Behaviours of Cylindrical Fatigue Specimens Made ...IRJET Journal
This document analyzes and compares the behaviors of cylindrical fatigue specimens made of nickel-titanium shape memory alloy and steel using finite element analysis in Abaqus. The modal frequencies and deformations were analyzed for the first 20 modes of each material. For both materials, higher order flexions occurred at higher frequencies. Tensile stress was highest in the gauge section and highest for steel due to its higher Young's modulus. The nickel-titanium alloy specimen had a lower maximum frequency, energy, and tensile stress compared to steel. Shape memory alloys are implemented in structures for vibration control and energy dissipation during earthquakes.
This document provides information on selecting fastener materials and their mechanical properties. It discusses the most common material, carbon steel, and its various grades. It also covers stainless steel types including austenitic, martensitic, and ferritic, and provides examples of common grades for each type. Additional materials discussed include alloy steels and precipitation hardening stainless steel. The document aims to provide basic knowledge on fastener materials to help with evaluating the right material for an application.
Review of shaft failure in Coil Car AssemblyIRJET Journal
This document summarizes a study on failures of shafts in coil car assemblies. The researchers investigated a failed coil car shaft and found that reversed bending fatigue caused it to fracture, occasionally due to misalignment. They calculated loads on the existing shaft theoretically and analytically and found the stresses exceeded permissible levels, indicating it was prone to failure. To improve shaft design, they examined increasing diameter and using fillets/chamfers to disperse stresses. A literature review showed other shaft failures were due to low radius of curvature, incorrect chamfer size increasing stress concentration, and vibrations from imbalance.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
The document discusses determining the fatigue behavior of engine damper cap screw bolts. It describes testing the bolts to determine their ultimate tensile strength, hardness, preload, and fatigue strength. Samples of the bolts were tested under various alternating loads with a constant mean load to generate an S-N curve showing their fatigue life. It was found that fatigue failure occurred in the threads due to high stress concentration, and the average preload of the bolts was determined to be 40,000 lbs using ultrasonic measurement.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
The document discusses determining the fatigue behavior of engine damper cap screw bolts. It begins with an abstract that outlines testing cap screw bolts under different alternating loads to determine their fatigue strength using the S-N method. It then provides background on issues like insufficient bolt preload leading to failure. The document describes testing the mechanical properties of damper cap screw bolts, including hardness, ultimate tensile strength from tension tests, and evaluating their chemical composition. It aims to determine the cap screw bolts' fatigue strength and failure locations under fatigue testing.
The document discusses design considerations for machine elements subjected to fluctuating loads. It covers topics such as stress concentration, fatigue failure, endurance limit, factors affecting fatigue strength, and methods to reduce stress concentration and improve fatigue life. Stress concentration occurs due to discontinuities and can be reduced by avoiding abrupt changes in cross-section and providing fillets. Fatigue failure is caused by fluctuating stresses and depends on factors like the number of cycles and mean stress. The endurance limit is the maximum stress amplitude a material can withstand without failure under completely reversed loading. Surface finish, size, and mean stress affect the endurance limit.
The document discusses stress concentration and fatigue failure in machine elements. It defines stress concentration as irregular stress distribution caused by abrupt changes in cross-section shape. Stress concentration factors are introduced to quantify the maximum stress compared to nominal stress. The document also discusses endurance limit and fatigue strength testing methods. Factors that affect fatigue strength like material properties, surface finish, size and temperature are summarized. Methods to evaluate and reduce stress concentration in designs are provided.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
This document provides an overview of basic design considerations for machine components. It discusses general design procedures and considerations, types of loads, stress-strain diagrams, types of stresses including tensile, compressive, shear, crushing, bearing, torsional, and bending stresses. It also covers concepts related to stress concentration, creep, fatigue, endurance limit, factor of safety, and theories of failure under static loads. Standard classifications and designations of various steel and alloy types are also presented.
Deflections in PT elements pt structure for all pt slabs in civil industry.pdfvijayvijay327286
The document discusses factors that influence deflections in prestressed concrete members and methods for predicting deflections. It covers:
- Short term deflections of unracked members which can be estimated using Mohr's theorem.
- How the tendon profile affects deflections, providing formulas for straight, trapezoidal, parabolic, and other tendon types.
- Downward deflections due to self-weight and imposed loads that can be calculated using formulas provided.
- Estimation of long-term deflections accounting for creep and shrinkage effects, discussing various methods like those of Busemann, McHenry, and Neville.
The document provides information about aircraft structures and structural analysis. It defines primary and secondary aircraft structures, and monocoque and semi-monocoque constructions. It describes the functions of different structural elements like the skin, ribs, spars, and stringers. It discusses simplifications made in structural analysis, including lumping longitudinal members and assuming webs only experience shear stresses. It also covers topics like unsymmetric bending, shear flow, shear centers, and torsion of thin-walled closed sections.
- Fatigue analysis aims to estimate the life of aircraft components under fluctuating cyclic loads.
- The stress-life (S-N) method relates the cyclic stress range to the number of cycles to failure and is commonly used. S-N curves are generated from testing and provide fatigue strength values.
- Stress concentrations around holes, notches, joints and other discontinuities significantly reduce the fatigue life of components and must be accounted for using stress concentration factors.
This document provides a review of limit load solutions for structural components containing defects. It summarizes existing limit load solutions for plates, cylinders, spheres, pipe bends, and shell/nozzle intersections with various defect geometries under different loading conditions. The solutions are useful for failure assessment methods that utilize the limit load or reference stress concept. Experimental verification of some solutions is also discussed, along with factors such as material and geometric hardening effects.
The document discusses different types of strain gauges used to measure strain. It describes how strain gauges work by changing electrical resistance proportionally to strain. Common types include metallic wire or foil grids bonded to a backing material. Materials like constantan/advance are often used due to properties like self-temperature compensation and linear strain sensitivity. Unbounded wire strain gauges consist of tensioned wires connected to a Wheatstone bridge circuit to measure strain through changes in electrical resistance. Strain gauges are widely applied to experimental stress analysis of structures, machines, vehicles and more.
IRJET- Forced Damped Vibration Analysis of Optimized Cantilever Beam using Di...IRJET Journal
This document summarizes a study on analyzing the forced damped vibration of an optimized cantilever beam using different methods. The study aims to identify a suitable material for manufacturing an engine casing by considering parameters like material, weight, damping coefficient, spring stiffness, and natural frequency. Using the Taguchi method and regression analysis, aluminum is identified as the optimal material. The natural frequency is then evaluated using theoretical, experimental (FFT analyzer), and simulation (ANSYS) methods. Time graphs and FFT readings from the experimental setup show peak frequencies that match the theoretical natural frequency of 5.36 Hz calculated using analytical methods.
The document discusses tensile strength and tensile testing. It defines tensile strength as the maximum stress a material can withstand under tension before necking and breaking. A tensile test measures how a material responds to tensile forces by recording the load and elongation of a test specimen. The results are displayed as a stress-strain curve which can show properties like yield strength, ultimate tensile strength, modulus of elasticity, and ductility measures.
The document discusses tensile strength and tensile testing. It defines tensile strength as the maximum stress a material can withstand under tension before necking and breaking. A tensile test measures how a material responds to tensile forces by recording the load and elongation of a test specimen. The results are used to determine various tensile properties including modulus of elasticity, yield strength, ultimate tensile strength, and measures of ductility. Hooke's law and concepts like strain, stress-strain curves, and necking are also explained in the context of understanding a material's tensile behavior.
Evaluation of Reduction in Compressive Strength of Singly Symmetric CFS Membe...IRJET Journal
This document presents a study evaluating the reduction in compressive strength of cold-formed steel lipped channel columns due to local buckling effects. A finite element analysis is conducted to analyze the behavior of fixed-ended and pinned-ended columns under compression. The analysis shows that local buckling causes a shift in the effective centroid for pinned columns, introducing overall bending and reducing capacity by up to 39% compared to fixed-ended columns. A parametric study is performed to evaluate the effects of cross-section dimensions, material properties, and slenderness ratios on column strength. Results are also compared to several design methods to evaluate their accuracy in predicting the behavior and strength of cold-formed steel columns.
Lecture 1 Single Mode Loading Part A.docDylanONeill11
This document discusses single-mode loading conditions that will be covered in the class, including axial loading, direct shear, torsional loading, and beam bending. It provides examples and equations for calculating stresses and deformations for each loading condition. For axial loading of a rod, it shows how to calculate the load at yield and ultimate failure. For direct shear, it discusses shear area and provides examples. For torsional loading, it introduces the torsion formula and shows how to calculate shear stresses. It also discusses stress concentrations and provides an example problem calculating maximum shear stress in a lawnmower drive shaft.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
2. 1. MODAL ANALYSIS
What is Modal Analysis?
• Structures are connected to the vibrating systems
• Excessive wear of bearings
• Noise
• Study of the dynamic properties of linear structures
• Helps to determine the vibration characteristics
• Natural frequency
3. 1. MODAL ANALYSIS
Why is Natural Frequency (Eigenfrequency)
• Frequency of the system when there is no force or damping factor
• Functions of mass, stiffness and boundary conditions
Why important?
• To understand possible resonance occurring
• Input data for transient dynamic analysis, harmonic analysis, random vibration etc.
Why is Resonance
• Oscillation of the structure at high amplitude with specific frequency
• Natural frequency coincides with the excitation frequency
• Can cause excessive deformation
4. 1. MODAL ANALYSIS
Geometry and Boundary Conditions
b=1m
a=2m
x
y
Formula of Natural Frequency Simply Supported Plate
ω𝑚𝑛 =
π2
D
ρ𝑚
h
m2
a2 +
n2
b2
2
Properties of Aluminum
E = 70 GPa
ρ = 2700 kg/m3
h = 2 mm
ν = 0.33
ω𝑚𝑛 = Natural circular frequency in radians per unit time
f𝑚𝑛 = Natural frequency of vibration in cycles per second (Hertz)
m = half wave no. of long edge
n = half wave no. of short edge
D = flexural stiffness
ρ𝑚 = density
h = thickness of plate
a = length of long edge
b = length of short edge
f𝑚𝑛 =
ω𝑚𝑛
2𝜋
Meaning of the Modes (m,n) (Mode Shapes)
b
a
y
z
n
x
z m
t
Example of
Mode (3,1)
D =
Eh3
12(1−ν2
)
Calculation Natural Frequency of the Plate
f11 =6.115 Hz
f21 =9.78 Hz
f31 = 15.9 Hz
f32 = 20.79 Hz
w
6. The substantiation of the installations will be carried out for flight condition limit loads with
pressurized fuel tank conditions. The MOS based on yield/ultimate strength have been presented
for substantiation and the MOS limit adopted is presented.
Analysis Failure Strength MOS limit
Flight condition
(limit loads)
Yield 0.15
Ultimate 0.50
Emergency crash
loading condition
Ultimate 0.00
MOS limit for different analysis & failure strength criteria
1. STRUCTURAL SUBSTANTION
7. The host structure of the installations are assumed to be made up of ___________
aluminum and having 5% MOS. Therefore, under flight condition limit loads ,the host
structur is substantiated when stresses are shown to be less than 5% of the yield
strength of _______ aluminum.
2. SUBSTANTION OF HOST STRUCTURE
8. • Bolts
The specification of the bolts ,i.e. the nominal diameter and minimum tensile
strength is obtained from the manual and consequently, the shear strength for
bolts (Ref. Bruhn )is taken as 1/√3 of the tensile strength. The ultimate single shear
load and ultimate tensile load of threaded fasteners are obtained from the
reference manual respectively .However, in the case of fastener where the ultimate
tensile & shear loads were not available in the reference doc the same was taken as
a product of minimum tensile/shear strength and effective cross-sectional area of
the respective fastener.
3. SUBSTANTION OF FASTENERS
9. The MOS for the bolt is expressed as,
Where
The fitting factor is taken as 1.15
3. SUBSTANTION OF FASTENERS
Ref. Bruhn. Analysis and Design of Flight Vehicle Structures.
Max shear load
10. • Unless otherwise specified a factor of safety of 1.5 must be applied to the limit load:
Ultimate load = 1.5 x limit load
The structure must be able to support ultimate loads without failure.
The structure must be able to support limit loads without detrimental permanent deformation.
3. SUBSTANTION OF FASTENERS
• The general procedure is to design a structure to zero margin. The Margin of Safety (MOS/MS) for the
stress analysis is equal to zero or greater, but is never a negative.
12. • Rivets
The specification of the rivets, i.e. the nominal diameter and minimum shear
strength is obtained from the references manual. Consequently, the allowable
tensile load is taken as 40% of the allowable shear load. The MOS is computed as
follows,
3. SUBSTANTION OF FASTENERS
13. The inertial loading for missile as per MIL-STD-8591, Appendix C shall be adopted
for the analysis. The load calculation equation and missile parameters are
mentioned below.
Case Condition
Load Factor (g)
FOS
nx ny nz
FC1
Cruise phase
- - 2.5
1.5
FC2 - - 1.5
FC3 - -1.5 -2.5
FC4 Boost phase 0.5/0.85 0.5/0.85
4. FLIGHT CONDITION LIMIT LOADS
14. The material properties have been taken from reference manual and their
parameters of the materials used are listed below.
Material
E
(Gpa)
µ
ρ
(kg/m3)
σy
(MPa)
σu
(MPa)
σby
(MPa)
σbu
(MPa)
AL 6061 T652 68.3 0.33 2713 241.32 262 372.32 420.58
5. MATERIAL PROPERTIES
15. LRU mass factor of 1.25 has been applied in the analysis that will account for the
wire bundle, miscellaneous mass and for any inaccuracy between the actual and
assumed CG. The CG for the LRU’s has been assumed to be at the geometric center
of the equipment.
6. LRU MASS FACTOR
16. • The finite element modelling has been performed using HyperMesh® and analysis using MSC
Nastran®. The post processing have been made using MSC Patran® (Stress plot) and HperView®
(Mode shapes and vibration response).
• In the finite element modelling, the mesh quality parameters used meshing is listed in Table 1. The
rivet/bolt holes have been modelled by having two rings of elements (eight elements in each) around
the hole (Figure 1), where the diameter of the ring is maintained at two times the diameter of the
hole.
• The bolts and rivets have been modelled as CBUSH elements (Figure 2) with translational stiffness of
106 along X, Y and Z direction and rotational stiffness of 108 about X, Y and Z directions, respectively.
• The LRU units are modelled as lumped masses at the LRU C.G. and element connectivity to the
structure is provided using RBE2 elements to their rivet/bolt connections (Figure 3 & 4).
• The installations meshed with QUAD4 & TRIA3 elements and the percentage ratio of TRIA3 to QUAD4
is maintained below 5%. The element size used for meshing is mentioned in individual sections of the
installations.
7. FINITE ELEMENT ANALYSIS
17. Parameters Value
Warpage <5
Aspect Ratio <5
Skewness 60
Jacobian >0.7
Triangular Element
Min. Angle (deg) >20
Max. Angle (deg) <120
Quadrilateral Element
Min. Angle (deg) >45
Max. Angle (deg) <135
Table 1: Adopted Mesh Quality Parameters
7. FINITE ELEMENT ANALYSIS
19. 8. PRE-TENSION LOAD ANALYSIS
• External loads (tensile) tend to separate members, bolt force cannot increase much unless the members
separate, the higher the preload the less likely the members are to separate.
• For external loads tending to shear the bolt, the higher the preload the greater the friction force resisting the
relative motion in shear.
• Higher preload reduces the dynamic load on the bolt because the effective area of the clamped members is
larger.
• Higher preload results in maximum protection against overloads, which can cause joint separation, and
provides protection against thread loosening.
P
P
P
P
20. 8. PRE-TENSION LOAD ANALYSIS
• Tightening torque related to preload and bolt diameter. The constant value, 0.2, remains approximately
the same regardless of the bolt size.
• For critical applications a torque wrench should be used to apply the proper preload.
• Initial tension (preload):
Ai – Tensile stress area; Sp – Proof strength
• Bolt should not be reused if tightened to 90% of the proof load, yielding may have occurred.
For static loads and permanent connection, tighten to 90% of the proof load.
For fatigue loading and non-permanent connections (reused fastener) tighten to 75% of the
proof load.
T = K*Pi*d
Pi = 0.75*Sp*Ai
K
(nut factor/friction factor/tightening factor)
Type of bolt
0.2 Steel bolts (with no plating)
0.15 Steel bolts with Cadmium plating
0.28 Steel bolt with Zinc plating
0.18 Steel bolts with lubrication
21. 8. PRE-TENSION LOAD ANALYSIS
• Calculate bolt preload as
σy – yield strength of the bolt material; F – external load applied on the bolt
• Equivalent stress
Stress by torsion is relaxed after tightening
equivalent stress should remain below the yield strength (linear elastic)
Pi = {[σy*(πD^2/4)]/FOS} - F
F
F
F
F
P
F+P
Total load
on the bolt
External load
on the flanges
σe = sqrt(σt^2 + 3τ^2)
22. 8. TYPES OF CONNECTIONS
• Mechanically fastened joints are conveniently classified according to the type of
forces to which the fasteners are subjected. These classes are (1) shear, (2) tension,
and (3) combined tension and shear. Under category 1 the fasteners are loaded
either in axial or eccentric shear. If the line of action of the applied load passes
through the centroid of the fasteners group, then the fasteners are loaded in axial
shear. In eccentric shear the shear force does not pass through the centroid of the
fastener group. This results in a torsional moment on the fastener group that increases
the fastener shear stresses. This loading condition is referred to as eccentric
shear.
23. • A system level approach is used in modeling fastener fixities as it is impractical to model actual fasteners.
• This approach assumes:
Fasteners and member interface is infinitely rigid
Shear and tensile loads are transmitted through the fastener joint
Contact between members is not modeled
In the max stress locations(cross piece) reacting fastener forces are mainly acting in the fastener tensile
direction therefore accounting for member friction will not greatly reduce resulting stress.
• It should be noted that stresses at the fixities will be unrealistic due to the nodal fixity and may causes an
artificially induced stress concentration (singularity). Unless stress values are below desired material
durability limits, the stresses in these areas are ignored and stress values are sampled away from the
singularity where stress values are not influenced by the singularity. Extracting detailed joint stresses
usually entails a detailed fastener analysis or a detailed such model.
9. SYSTEM LEVEL APPROACH