Nkundineza, Celestin_PhDDissertationDefense_112015
•
0 likes•136 views
This dissertation examines how variations in railroad track stiffness and inclusions within rails can impact fatigue life. A computational model uses finite element analysis of hundreds of rail sections across representative track geometries. Field measurement data is used to estimate model parameters. Results show nonuniform track beds can reduce fatigue life up to 100 times compared to uniform tracks. Inclusion location and stiffness also influence fatigue life and crack propagation direction. Understanding these factors could help improve rail maintenance and inspection scheduling.
Report
Share
Report
Share
Download to read offline
Recommended
paper
This document analyzes the nonlinear dynamic behavior of functionally graded micro-pipes conveying fluid using strain gradient theory. It develops mathematical formulations based on the Euler-Bernoulli beam model and von Kármán geometric nonlinearity. The properties of the functionally graded micro-pipes vary according to a power law distribution across the thickness. Hamilton's principle is used to obtain the differential equation of motion and boundary conditions for simply supported pipes. Galerkin's method expresses the governing equation as a Duffing equation. The homotopy analysis method is then used to determine explicit expressions for the nonlinear fundamental frequency for different fluid velocities and power law indices.
Track state modelling tool
Matthew Audley is pursuing a PhD in track maintenance decision making under the supervision of Professor John Andrews. The study analyzes six years of UK rail network track geometry and maintenance data to understand the effects of maintenance on track deterioration. A Weibull approach is used to model the time it takes track geometry to degrade after maintenance. The results show that traffic speed and maintenance history impact deterioration rates. The second half of the PhD develops a track state modeling tool using Petri nets to determine optimal inspection intervals, maintenance criteria, and resource allocation to minimize life cycle costs.
Coupling effects between wind and train transit induced fatigue damage in sus...
Long-span steel suspension bridges develop significant vibrations under the effect of external time-variable loadings because their slenderness. This causes significant stresses variations that could induce fatigue problems in critical components of the bridge. The research outcome presented in this paper includes a fatigue analysis of a long suspension bridge with 3300 meters central suspended span under wind action and train transit. Special focus is made on the counterintuitive interaction effects between train and wind loads in terms of fatigue damage accumulation in the hanger ropes. In fact the coupling of the two actions is shown to have positive effects for some hangers in terms of damage accumulation. Fatigue damage is evaluated using a linear accumulation model (Palmgren-Miner rule), analyses are carried out in time domain by a three-dimensional non-linear finite element model of the bridge. Rational explanation regarding the above-mentioned counterintuitive behavior is given on the basis of the stress time histories obtained for pertinent hangers under the effects of wind and train as acting separately or simultaneously. The interaction between wind and train traffic loads can be critical for a some hanger ropes therefore interaction phenomena within loads should be considered in the design.
Optimum Dimensions of Suspension Bridges Considering Natural Period
Abstract: Suspension bridge is an efficient structural system particularly for large spans. Many difficulties
related to design and construction feasibility arises due to its long central span. There are many suspension
bridges around the world and dynamic behavior has been found to be the primary concern for those bridges.
Natural period of a suspension bridge mainly dependent on the span and other structural dimensions related to
the stiffness. In the present study, the effects of structural parameters like deck depth and tower height on
natural period of suspension bridges having different central spans are conducted. Natural periods are
analyzed by modal analysis for central span lengths ranges from 600m to 1400m. The modal analysis is
performed by finite element software package SAP2000. For each central span, tower heights and deck depth
are varied and the consequences of these variations on the natural periods of various types of vibration modes
are investigated and dominant mode for each span is recognized. Obtained values from the analysis were
utilized to plot three dimensional surfaces representing correlation among natural period, deck depth, tower
height, and span, using MATLAB functions. A relationship among tentative optimum deck depth, optimum tower
height and central span of suspension bridge is developed for obtaining minimum natural period. This
relationship can be used to obtain the tentative optimum dimensions of a suspension bridge with central span
between 600m to 1400m.
Keywords: suspension bridge, natural period, optimum dimensions, modal analysis.
Profiled Deck Composite Slab Strength Verification: A Review
This document reviews different methods for verifying the strength of profiled deck composite slabs (PDCS) without expensive laboratory testing. It discusses two common methods - the slope-intercept method and partial shear connection method - which both require experimental test data. The document also reviews attempts to use numerical modeling as an alternative to testing, but notes limitations in accurately modeling the complex shear behavior. It concludes that laboratory testing remains the most accurate assessment of PDCS strength, and further work is needed to develop a rational, reliability-based numerical approach to determine strength without testing.
1467782670 5 ijaems-jun-2016-49-finite element analysis for the buckling load...
1467782670 5 ijaems-jun-2016-49-finite element analysis for the buckling load...INFOGAIN PUBLICATION
The buckling behavior of the geometry subjected to static loading (compression) is presented. The columns under consideration were made with corrugation perpendicular to the line of action which coincides exactly with the unstrained axis of the column. Four different arrangements of tubes have been considered for all the conditions taken into consideration. The thickness of the tubes, the number of corrugation, and diameter of the tubes, pitch and depth of the tubes have been varied accordingly. Analysis of the prepared tubes was performed using ANSYS 17.0. A linear buckling analysis was performed to calculate the critical load of the corrugated tubes. The effect of buckling and maximum critical load of the FEM models are discussed. Pqct group 281-29%282%29
This document discusses methods for assessing bone strength beyond bone mineral density (BMD) measurements. Computed tomography (CT) allows assessment of additional factors like bone shape, muscle, and fat content to better determine bone strength. Dual energy X-ray absorptiometry (DEXA) accurately measures BMD but does not provide full picture of mechanical strength. A study used peripheral quantitative CT to scan subjects' left and right forearms, finding significant differences in bone strength, density, and area between dominant and non-dominant sides. Combining BMD with other structural factors enables more precise bone strength assessment than BMD alone.
An investigation of effects of axle load and train speed at rail joint using ...
An investigation of effects of axle load and train speed at rail joint using ...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.Recommended
paper
This document analyzes the nonlinear dynamic behavior of functionally graded micro-pipes conveying fluid using strain gradient theory. It develops mathematical formulations based on the Euler-Bernoulli beam model and von Kármán geometric nonlinearity. The properties of the functionally graded micro-pipes vary according to a power law distribution across the thickness. Hamilton's principle is used to obtain the differential equation of motion and boundary conditions for simply supported pipes. Galerkin's method expresses the governing equation as a Duffing equation. The homotopy analysis method is then used to determine explicit expressions for the nonlinear fundamental frequency for different fluid velocities and power law indices.
Track state modelling tool
Matthew Audley is pursuing a PhD in track maintenance decision making under the supervision of Professor John Andrews. The study analyzes six years of UK rail network track geometry and maintenance data to understand the effects of maintenance on track deterioration. A Weibull approach is used to model the time it takes track geometry to degrade after maintenance. The results show that traffic speed and maintenance history impact deterioration rates. The second half of the PhD develops a track state modeling tool using Petri nets to determine optimal inspection intervals, maintenance criteria, and resource allocation to minimize life cycle costs.
Coupling effects between wind and train transit induced fatigue damage in sus...
Long-span steel suspension bridges develop significant vibrations under the effect of external time-variable loadings because their slenderness. This causes significant stresses variations that could induce fatigue problems in critical components of the bridge. The research outcome presented in this paper includes a fatigue analysis of a long suspension bridge with 3300 meters central suspended span under wind action and train transit. Special focus is made on the counterintuitive interaction effects between train and wind loads in terms of fatigue damage accumulation in the hanger ropes. In fact the coupling of the two actions is shown to have positive effects for some hangers in terms of damage accumulation. Fatigue damage is evaluated using a linear accumulation model (Palmgren-Miner rule), analyses are carried out in time domain by a three-dimensional non-linear finite element model of the bridge. Rational explanation regarding the above-mentioned counterintuitive behavior is given on the basis of the stress time histories obtained for pertinent hangers under the effects of wind and train as acting separately or simultaneously. The interaction between wind and train traffic loads can be critical for a some hanger ropes therefore interaction phenomena within loads should be considered in the design.
Optimum Dimensions of Suspension Bridges Considering Natural Period
Abstract: Suspension bridge is an efficient structural system particularly for large spans. Many difficulties
related to design and construction feasibility arises due to its long central span. There are many suspension
bridges around the world and dynamic behavior has been found to be the primary concern for those bridges.
Natural period of a suspension bridge mainly dependent on the span and other structural dimensions related to
the stiffness. In the present study, the effects of structural parameters like deck depth and tower height on
natural period of suspension bridges having different central spans are conducted. Natural periods are
analyzed by modal analysis for central span lengths ranges from 600m to 1400m. The modal analysis is
performed by finite element software package SAP2000. For each central span, tower heights and deck depth
are varied and the consequences of these variations on the natural periods of various types of vibration modes
are investigated and dominant mode for each span is recognized. Obtained values from the analysis were
utilized to plot three dimensional surfaces representing correlation among natural period, deck depth, tower
height, and span, using MATLAB functions. A relationship among tentative optimum deck depth, optimum tower
height and central span of suspension bridge is developed for obtaining minimum natural period. This
relationship can be used to obtain the tentative optimum dimensions of a suspension bridge with central span
between 600m to 1400m.
Keywords: suspension bridge, natural period, optimum dimensions, modal analysis.
Profiled Deck Composite Slab Strength Verification: A Review
This document reviews different methods for verifying the strength of profiled deck composite slabs (PDCS) without expensive laboratory testing. It discusses two common methods - the slope-intercept method and partial shear connection method - which both require experimental test data. The document also reviews attempts to use numerical modeling as an alternative to testing, but notes limitations in accurately modeling the complex shear behavior. It concludes that laboratory testing remains the most accurate assessment of PDCS strength, and further work is needed to develop a rational, reliability-based numerical approach to determine strength without testing.
1467782670 5 ijaems-jun-2016-49-finite element analysis for the buckling load...
1467782670 5 ijaems-jun-2016-49-finite element analysis for the buckling load...INFOGAIN PUBLICATION
The buckling behavior of the geometry subjected to static loading (compression) is presented. The columns under consideration were made with corrugation perpendicular to the line of action which coincides exactly with the unstrained axis of the column. Four different arrangements of tubes have been considered for all the conditions taken into consideration. The thickness of the tubes, the number of corrugation, and diameter of the tubes, pitch and depth of the tubes have been varied accordingly. Analysis of the prepared tubes was performed using ANSYS 17.0. A linear buckling analysis was performed to calculate the critical load of the corrugated tubes. The effect of buckling and maximum critical load of the FEM models are discussed. Pqct group 281-29%282%29
This document discusses methods for assessing bone strength beyond bone mineral density (BMD) measurements. Computed tomography (CT) allows assessment of additional factors like bone shape, muscle, and fat content to better determine bone strength. Dual energy X-ray absorptiometry (DEXA) accurately measures BMD but does not provide full picture of mechanical strength. A study used peripheral quantitative CT to scan subjects' left and right forearms, finding significant differences in bone strength, density, and area between dominant and non-dominant sides. Combining BMD with other structural factors enables more precise bone strength assessment than BMD alone.
An investigation of effects of axle load and train speed at rail joint using ...
An investigation of effects of axle load and train speed at rail joint using ...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.Poster at SC conference 2016
Rolling Contact Fatigue (RCF) Analysis of a Railway Wheel Using ABAQUS Through Texas A&M University High Performance Research Computing
B05
This document summarizes research on using a passive vibration damping system in a telecommunication tower. A finite element model was developed to simulate the dynamic behavior of a 40m tall truss tower. Simulation results showed that installing a viscoelastic damper below the service platform could reduce tower vibration amplitudes and member forces by half. The damper mass was connected to the tower apex nodes by three viscoelastic elements modeled as springs and dashpots. The goal was to determine damper parameters that provide maximum damping effectiveness through minimizing tower vibrations.
Rail Structure Interaction Analysis of Steel Composite Metro Bridge
This document summarizes a study on rail structure interaction analysis of a steel composite metro bridge in Mumbai, India. The study uses 3D finite element modeling software to analyze stresses in the rails due to temperature variations and train loads. The total bridge length analyzed is 743.43 meters, of which 260.43 meters is steel composite. The objectives are to determine additional rail stresses and bearing forces, and check if stresses are within permissible limits set by standards. Nonlinear springs are used to model the connection between rails and deck, and results will show axial rail stresses along the bridge length.
Dr-degree
This document discusses research on improving the rolling contact fatigue wear resistance of train track alloy steel through laser processing of biomimetic coupling units on the steel surface. Key points:
1) Biomimetic units with different striation angles (30°, 45°, 60°) were created on alloy steel samples using laser remelting to mimic structures found in nature.
2) Testing found the samples with units had significantly less mass loss than untreated samples when subjected to rolling contact fatigue wear testing, indicating better wear resistance.
3) Samples with 30° and 60° striation units performed best, with mass loss reductions of 85% and 86.3% respectively, compared to 73.9% for the 45
Experimental investigation on torsion bar suspension system using e glass fi...
Experimental investigation on torsion bar suspension system using e glass fi...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and TechnologyAnalysis and Design of Transmission Tower
Electrical Engineering,Mechanical Engineering,Computer Science & Engineering,Artificial Intelligence,Material Science,Mathematicse,Applied physics,Applied Chemistry,Electronics Engineering,Instrumentation Engineering,Civil Engineering,Earth quake Engineering,Structural engineering,
The effective width in multi girder composite steel beams with web openings
This document summarizes a study on the effective width of multi-girder composite steel beams with web openings through finite element analysis. Several 3D models were developed to examine the effects of varying slab thickness, slab width, span length, and load type. The analysis found that thicker slabs experience less shear lag due to higher shear stiffness. Wider slabs and shorter spans also decreased shear lag effects. Different load types produced varying stress distributions across the slab width, affecting the effective width.
2015465.pdf
This research article presents a linearized model for vehicle-track interactions. The key aspects are:
1) A wheel-rail interaction element is derived that considers both wheel-rail contact and separation conditions. It includes the effects of linear creepage and gravitational restoring forces.
2) Coupling matrices are developed to connect the wheel-rail interaction element to other vehicle and track components.
3) An equation of motion is established for the unified linearized vehicle-track system.
4) Numerical examples compare the linear model to a nonlinear model and evaluate using it for random vibration analysis to predict system response safety margins.
Sensor Placement based on FE Modal Analysis: Dynamic Characteristic of Cable ...
This document summarizes a study that used finite element analysis to determine sensor placement locations for structural health monitoring of the Penang (I) cable-stayed bridge in Malaysia. The researchers created a 3D finite element model of the bridge and performed modal analysis to determine its natural frequencies and vibration modes under dead load conditions. They identified critical grid points on the bridge members that experienced high stresses due to vibration. They proposed 66 sensor placement locations corresponding to these grid points, including locations at the end side spans, towers, main span, and stay cables. The sensor locations were aimed at monitoring the dynamic behavior and structural health of the bridge.
Analysis of Crack Severity on Power Density Increment of Gears
Helical gears are commonly used in industry as
they have advantages of higher power density, quieter
operation etc., compared to spur gears. Conventional gear
design is based on various design criteria, including durability
and bending strength load rating. In recent times, fracture
failure modes are gaining importance in addition to
conventional failure modes. Stresses due to operating fatigue
loads and internal residual stresses can cause fatigue fracture
failure on the surface, sub-surface of gear flanks or at tooth
root of gears. During gear design, various parameters are
optimized, and one such parameter is the helix angle that is
optimized for power density and gear noise. However, effect of
possible defects (voids and inclusions) in the gear tooth is not
usually considered in these calculations. This paper is a study
on severity of defects in a gear blank relative to power density
increment. Three different gear geometries (spur and helical
gears with two different helix angles) each with similar defects
are considered. Finite Element Analysis (FEA) is used to
analyze Tooth Interior Fracture (TIF), and study variation of
Stress Intensity Factor (SIF) with crack size and helix angle.
It is seen that power density increment of a common gear
blank through helix angle increment poses a higher risk of
crack severity, as the same gear blank is exposed to higher
operating loads.
Fatigue behavior of high volume fly ash
This document discusses the fatigue behavior of high volume fly ash concrete (HVFAC) under constant amplitude and compound loading. It presents test results of 95 HVFAC and 100 conventional concrete prism specimens tested under constant amplitude flexural fatigue loading. It also discusses test results of 24 HVFAC specimens under compound fatigue loading to verify the validity of Miner's hypothesis for HVFAC. Probability distributions were developed from the fatigue life test results and S-N curves were established relating stress level to fatigue life for both concretes. The findings provide useful data on fatigue performance of HVFAC.
Effects of Vehicle Running Mode on Rail Potential and Stray Current in DC Mas...
The document discusses how different vehicle running modes impact rail potential and stray current in DC mass transit systems. Field tests on Nanjing Metro Line 1 showed that rail potential was highest in the acceleration and brake modes of vehicles. Specifically, the maximum positive potential occurred during acceleration, while the maximum negative potential was observed during braking. Numerical simulations also indicated that rail potential is significantly higher in acceleration and braking modes compared to other running modes like coasting. The vehicle running mode was found to influence both the rail potential and shifts in buried conductor potential within stray currents.
Experimental stress analysis and fea of dental implants
Abstract Dental implants are used as prosthetic treatment alternatives made of Titanium for treating partial edentulism in patients. The
oessointegration of bone and implant at the interface is of utmost importance as the success or failure of a dental implant depends
on the manner in which stresses are transferred to the surrounding bone. The osseointegrated dental implant plays a role similar
to that of natural teeth as it is exposed to static and dynamic loadings continuously. However, the functional forces in
Osseointegrated dental implant are transmitted directly to the jaw bone as compared to the natural teeth where there is a healthy
periodontium. This could cause micro-fracture at the bone-implant interface, fracture of implant, loosening of components of
implant system and unwanted bone resorption. Therefore, it is essential to understand stress concentration on implants at the
bone implant interface. This study aims in investigating and monitoring the stresses along the bone implant interface for different
types of dental implant .Photo elastic stress analysis was carried on four commercial implants with varying diameter and same
length, and the verification of the experimental results was done using finite element analysis.
Keywords: Dental Implant, Photoelasticity, Stress Analysis, Implant Bone Interface, FEA
THE EFFECT OF LATERAL CONFIGURATION ON STATIC AND DYNAMIC BEHAVIOUR OF LONG S...
Long span bridge is the demand of every nation and it could be achieved with use of enhanced materials. With the development of the high strength materials and techniques for analysis of bridge, long span cable supported bridge are introduced. Generally, cable supported bridges comprise both suspension and cable-stayed bridge. Cable supported bridges are flexible in behavior. These flexible systems are susceptible to the dynamic effects of wind and earthquake loads. With increasing span of the bridge the flexibility of the bridge is increasing. Here, attempt is made to improve the rigidity of long span bridge and presented in this research paper. For enhancing the rigidity of the bridge in lateral and vertical directions, different configuration of the cables of long span cable supported bridges is considered in this study.
Fault identification in transformer winding
This document discusses fault identification in transformer windings during impulse testing. It presents an analysis of transformer winding current waveforms using both time-domain and frequency-domain (Fast Fourier Transform) methods to classify insulation failures. Simulation results are shown for a range of distribution transformer models with different fault types created at various locations. The proposed approach is applied to an analog model of a 12kVA single-phase transformer, with faults detected by analyzing the neutral currents under applied low voltage impulses.
Fault identification in transformer winding
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Sharma2016 development of probabilistic fatigue curve for asphalt concrete
This document presents a novel methodology for developing probabilistic fatigue curves for asphalt concrete based on viscoelastic continuum damage mechanics. Several asphalt concrete specimens were tested under uniaxial loading to determine their viscoelastic and damage properties. The data was analyzed using viscoelastic continuum damage mechanics principles to predict fatigue life. Weibull and lognormal distributions were fit to the predicted fatigue lives. The Weibull distribution provided the best fit to the fatigue damage data. A 3-parameter Weibull distribution fit better than a 2-parameter distribution due to its flexibility. The probabilistic fatigue curves developed differed significantly from traditional deterministic curves. The proposed methodology combines continuum damage mechanics with probabilistic approaches.
Energy efficiency of railway lines
This document discusses energy efficiency in railway transportation across three key areas: railway infrastructure, traffic management, and dynamic train movement.
1) Railway infrastructure, such as line gradients and curvatures, have a significant impact on energy consumption for train haulage. Steeper gradients and tighter curves increase resistance and energy use.
2) Traffic management procedures, like station design and use of automatic block systems, also influence energy efficiency. Level crossings and stopping before signals cause unnecessary braking and acceleration that waste energy.
3) Dynamic train movement parameters including weight, speed, and acceleration must be optimized given the infrastructure. Heavier trains and higher speeds increase energy consumption.
DESIGN AND ANALYSIS OF BRIDGE WITH TWO ENDS FIXED ON VERTICAL WALL USING FIN...
The Finite element analyses are conducted to model the tensile capacity of steel fiber-reinforced concrete (SFRC). For this purpose bridge with two ends fixed one specimen are casted and tested under direct and uni-axial tension. Two types of aggregates (brick and stone) are used to cast the SFRC and plain concrete. The fiber volume ratio is maintained 1.5 %. Total 8 numbers of dog-bone specimens are made and tested in a 1000-kN capacity digital universal testing machine (UTM). The strain data are gathered employing digital image correlation technique from high-definition images and high-speed video clips. Then, the strain data are synthesized with the load data obtained from the load cell of the UTM.
Literature work study of precast concrete connections in seismic
1. The document summarizes several studies on precast concrete connections, focusing on beam-column connections.
2. Key findings from the literature include that ductile connections can be designed to withstand seismic forces if connecting elements are used, and that hybrid post-tensioned and Dywidag Ductile connector systems have shown promise in seismic regions.
3. Finite element modeling studies found that accounting for shear transfer through vertical joints between precast wall panels provides more accurate force estimates than models neglecting this effect.
More Related Content
Similar to Nkundineza, Celestin_PhDDissertationDefense_112015
Poster at SC conference 2016
Rolling Contact Fatigue (RCF) Analysis of a Railway Wheel Using ABAQUS Through Texas A&M University High Performance Research Computing
B05
This document summarizes research on using a passive vibration damping system in a telecommunication tower. A finite element model was developed to simulate the dynamic behavior of a 40m tall truss tower. Simulation results showed that installing a viscoelastic damper below the service platform could reduce tower vibration amplitudes and member forces by half. The damper mass was connected to the tower apex nodes by three viscoelastic elements modeled as springs and dashpots. The goal was to determine damper parameters that provide maximum damping effectiveness through minimizing tower vibrations.
Rail Structure Interaction Analysis of Steel Composite Metro Bridge
This document summarizes a study on rail structure interaction analysis of a steel composite metro bridge in Mumbai, India. The study uses 3D finite element modeling software to analyze stresses in the rails due to temperature variations and train loads. The total bridge length analyzed is 743.43 meters, of which 260.43 meters is steel composite. The objectives are to determine additional rail stresses and bearing forces, and check if stresses are within permissible limits set by standards. Nonlinear springs are used to model the connection between rails and deck, and results will show axial rail stresses along the bridge length.
Dr-degree
This document discusses research on improving the rolling contact fatigue wear resistance of train track alloy steel through laser processing of biomimetic coupling units on the steel surface. Key points:
1) Biomimetic units with different striation angles (30°, 45°, 60°) were created on alloy steel samples using laser remelting to mimic structures found in nature.
2) Testing found the samples with units had significantly less mass loss than untreated samples when subjected to rolling contact fatigue wear testing, indicating better wear resistance.
3) Samples with 30° and 60° striation units performed best, with mass loss reductions of 85% and 86.3% respectively, compared to 73.9% for the 45
Experimental investigation on torsion bar suspension system using e glass fi...
Experimental investigation on torsion bar suspension system using e glass fi...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and TechnologyAnalysis and Design of Transmission Tower
Electrical Engineering,Mechanical Engineering,Computer Science & Engineering,Artificial Intelligence,Material Science,Mathematicse,Applied physics,Applied Chemistry,Electronics Engineering,Instrumentation Engineering,Civil Engineering,Earth quake Engineering,Structural engineering,
The effective width in multi girder composite steel beams with web openings
This document summarizes a study on the effective width of multi-girder composite steel beams with web openings through finite element analysis. Several 3D models were developed to examine the effects of varying slab thickness, slab width, span length, and load type. The analysis found that thicker slabs experience less shear lag due to higher shear stiffness. Wider slabs and shorter spans also decreased shear lag effects. Different load types produced varying stress distributions across the slab width, affecting the effective width.
2015465.pdf
This research article presents a linearized model for vehicle-track interactions. The key aspects are:
1) A wheel-rail interaction element is derived that considers both wheel-rail contact and separation conditions. It includes the effects of linear creepage and gravitational restoring forces.
2) Coupling matrices are developed to connect the wheel-rail interaction element to other vehicle and track components.
3) An equation of motion is established for the unified linearized vehicle-track system.
4) Numerical examples compare the linear model to a nonlinear model and evaluate using it for random vibration analysis to predict system response safety margins.
Sensor Placement based on FE Modal Analysis: Dynamic Characteristic of Cable ...
This document summarizes a study that used finite element analysis to determine sensor placement locations for structural health monitoring of the Penang (I) cable-stayed bridge in Malaysia. The researchers created a 3D finite element model of the bridge and performed modal analysis to determine its natural frequencies and vibration modes under dead load conditions. They identified critical grid points on the bridge members that experienced high stresses due to vibration. They proposed 66 sensor placement locations corresponding to these grid points, including locations at the end side spans, towers, main span, and stay cables. The sensor locations were aimed at monitoring the dynamic behavior and structural health of the bridge.
Analysis of Crack Severity on Power Density Increment of Gears
Helical gears are commonly used in industry as
they have advantages of higher power density, quieter
operation etc., compared to spur gears. Conventional gear
design is based on various design criteria, including durability
and bending strength load rating. In recent times, fracture
failure modes are gaining importance in addition to
conventional failure modes. Stresses due to operating fatigue
loads and internal residual stresses can cause fatigue fracture
failure on the surface, sub-surface of gear flanks or at tooth
root of gears. During gear design, various parameters are
optimized, and one such parameter is the helix angle that is
optimized for power density and gear noise. However, effect of
possible defects (voids and inclusions) in the gear tooth is not
usually considered in these calculations. This paper is a study
on severity of defects in a gear blank relative to power density
increment. Three different gear geometries (spur and helical
gears with two different helix angles) each with similar defects
are considered. Finite Element Analysis (FEA) is used to
analyze Tooth Interior Fracture (TIF), and study variation of
Stress Intensity Factor (SIF) with crack size and helix angle.
It is seen that power density increment of a common gear
blank through helix angle increment poses a higher risk of
crack severity, as the same gear blank is exposed to higher
operating loads.
Fatigue behavior of high volume fly ash
This document discusses the fatigue behavior of high volume fly ash concrete (HVFAC) under constant amplitude and compound loading. It presents test results of 95 HVFAC and 100 conventional concrete prism specimens tested under constant amplitude flexural fatigue loading. It also discusses test results of 24 HVFAC specimens under compound fatigue loading to verify the validity of Miner's hypothesis for HVFAC. Probability distributions were developed from the fatigue life test results and S-N curves were established relating stress level to fatigue life for both concretes. The findings provide useful data on fatigue performance of HVFAC.
Effects of Vehicle Running Mode on Rail Potential and Stray Current in DC Mas...
The document discusses how different vehicle running modes impact rail potential and stray current in DC mass transit systems. Field tests on Nanjing Metro Line 1 showed that rail potential was highest in the acceleration and brake modes of vehicles. Specifically, the maximum positive potential occurred during acceleration, while the maximum negative potential was observed during braking. Numerical simulations also indicated that rail potential is significantly higher in acceleration and braking modes compared to other running modes like coasting. The vehicle running mode was found to influence both the rail potential and shifts in buried conductor potential within stray currents.
Experimental stress analysis and fea of dental implants
Abstract Dental implants are used as prosthetic treatment alternatives made of Titanium for treating partial edentulism in patients. The
oessointegration of bone and implant at the interface is of utmost importance as the success or failure of a dental implant depends
on the manner in which stresses are transferred to the surrounding bone. The osseointegrated dental implant plays a role similar
to that of natural teeth as it is exposed to static and dynamic loadings continuously. However, the functional forces in
Osseointegrated dental implant are transmitted directly to the jaw bone as compared to the natural teeth where there is a healthy
periodontium. This could cause micro-fracture at the bone-implant interface, fracture of implant, loosening of components of
implant system and unwanted bone resorption. Therefore, it is essential to understand stress concentration on implants at the
bone implant interface. This study aims in investigating and monitoring the stresses along the bone implant interface for different
types of dental implant .Photo elastic stress analysis was carried on four commercial implants with varying diameter and same
length, and the verification of the experimental results was done using finite element analysis.
Keywords: Dental Implant, Photoelasticity, Stress Analysis, Implant Bone Interface, FEA
THE EFFECT OF LATERAL CONFIGURATION ON STATIC AND DYNAMIC BEHAVIOUR OF LONG S...
Long span bridge is the demand of every nation and it could be achieved with use of enhanced materials. With the development of the high strength materials and techniques for analysis of bridge, long span cable supported bridge are introduced. Generally, cable supported bridges comprise both suspension and cable-stayed bridge. Cable supported bridges are flexible in behavior. These flexible systems are susceptible to the dynamic effects of wind and earthquake loads. With increasing span of the bridge the flexibility of the bridge is increasing. Here, attempt is made to improve the rigidity of long span bridge and presented in this research paper. For enhancing the rigidity of the bridge in lateral and vertical directions, different configuration of the cables of long span cable supported bridges is considered in this study.
Fault identification in transformer winding
This document discusses fault identification in transformer windings during impulse testing. It presents an analysis of transformer winding current waveforms using both time-domain and frequency-domain (Fast Fourier Transform) methods to classify insulation failures. Simulation results are shown for a range of distribution transformer models with different fault types created at various locations. The proposed approach is applied to an analog model of a 12kVA single-phase transformer, with faults detected by analyzing the neutral currents under applied low voltage impulses.
Fault identification in transformer winding
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Sharma2016 development of probabilistic fatigue curve for asphalt concrete
This document presents a novel methodology for developing probabilistic fatigue curves for asphalt concrete based on viscoelastic continuum damage mechanics. Several asphalt concrete specimens were tested under uniaxial loading to determine their viscoelastic and damage properties. The data was analyzed using viscoelastic continuum damage mechanics principles to predict fatigue life. Weibull and lognormal distributions were fit to the predicted fatigue lives. The Weibull distribution provided the best fit to the fatigue damage data. A 3-parameter Weibull distribution fit better than a 2-parameter distribution due to its flexibility. The probabilistic fatigue curves developed differed significantly from traditional deterministic curves. The proposed methodology combines continuum damage mechanics with probabilistic approaches.
Energy efficiency of railway lines
This document discusses energy efficiency in railway transportation across three key areas: railway infrastructure, traffic management, and dynamic train movement.
1) Railway infrastructure, such as line gradients and curvatures, have a significant impact on energy consumption for train haulage. Steeper gradients and tighter curves increase resistance and energy use.
2) Traffic management procedures, like station design and use of automatic block systems, also influence energy efficiency. Level crossings and stopping before signals cause unnecessary braking and acceleration that waste energy.
3) Dynamic train movement parameters including weight, speed, and acceleration must be optimized given the infrastructure. Heavier trains and higher speeds increase energy consumption.
DESIGN AND ANALYSIS OF BRIDGE WITH TWO ENDS FIXED ON VERTICAL WALL USING FIN...
The Finite element analyses are conducted to model the tensile capacity of steel fiber-reinforced concrete (SFRC). For this purpose bridge with two ends fixed one specimen are casted and tested under direct and uni-axial tension. Two types of aggregates (brick and stone) are used to cast the SFRC and plain concrete. The fiber volume ratio is maintained 1.5 %. Total 8 numbers of dog-bone specimens are made and tested in a 1000-kN capacity digital universal testing machine (UTM). The strain data are gathered employing digital image correlation technique from high-definition images and high-speed video clips. Then, the strain data are synthesized with the load data obtained from the load cell of the UTM.
Literature work study of precast concrete connections in seismic
1. The document summarizes several studies on precast concrete connections, focusing on beam-column connections.
2. Key findings from the literature include that ductile connections can be designed to withstand seismic forces if connecting elements are used, and that hybrid post-tensioned and Dywidag Ductile connector systems have shown promise in seismic regions.
3. Finite element modeling studies found that accounting for shear transfer through vertical joints between precast wall panels provides more accurate force estimates than models neglecting this effect.
Similar to Nkundineza, Celestin_PhDDissertationDefense_112015 (20)
Rail Structure Interaction Analysis of Steel Composite Metro Bridge
Rail Structure Interaction Analysis of Steel Composite Metro Bridge
Experimental investigation on torsion bar suspension system using e glass fi...
Experimental investigation on torsion bar suspension system using e glass fi...
The effective width in multi girder composite steel beams with web openings
The effective width in multi girder composite steel beams with web openings
Sensor Placement based on FE Modal Analysis: Dynamic Characteristic of Cable ...
Sensor Placement based on FE Modal Analysis: Dynamic Characteristic of Cable ...
Analysis of Crack Severity on Power Density Increment of Gears
Analysis of Crack Severity on Power Density Increment of Gears
Effects of Vehicle Running Mode on Rail Potential and Stray Current in DC Mas...
Effects of Vehicle Running Mode on Rail Potential and Stray Current in DC Mas...
Experimental stress analysis and fea of dental implants
Experimental stress analysis and fea of dental implants
THE EFFECT OF LATERAL CONFIGURATION ON STATIC AND DYNAMIC BEHAVIOUR OF LONG S...
THE EFFECT OF LATERAL CONFIGURATION ON STATIC AND DYNAMIC BEHAVIOUR OF LONG S...
Sharma2016 development of probabilistic fatigue curve for asphalt concrete
Sharma2016 development of probabilistic fatigue curve for asphalt concrete
DESIGN AND ANALYSIS OF BRIDGE WITH TWO ENDS FIXED ON VERTICAL WALL USING FIN...
DESIGN AND ANALYSIS OF BRIDGE WITH TWO ENDS FIXED ON VERTICAL WALL USING FIN...
Literature work study of precast concrete connections in seismic
Literature work study of precast concrete connections in seismic
Nkundineza, Celestin_PhDDissertationDefense_112015
- 1. Railroad transportation is very important for economic growth and effective maintenance is one critical factor for its economic sustainability. The high repetitive forces from a moving railcar induce cyclic stresses that lead to rail bending and potential deterioration due to fatigue crack initiation and propagation. Previous research for prediction of fatigue life has been done under the assumption of a uniform track bed and a homogeneous rail. However the variation of the track stiffness is expected to increase the maximum stresses in the rail and, therefore, accelerates the fatigue process. The research described in this dissertation is focused on the variations of the track modulus as well as the inclusions within the rail and their role on fatigue life. The computational procedure is based on the automated preprocessing and post processing of the several hundreds of finite element models of the rail across a set of crossties chosen from a random ensemble with representative statistical variations. The model parameters are estimated from the field track deflection dynamic measurement data in the comparison with deflection data from FE models. A multiaxial fatigue model is used for the estimation of fatigue cycles to crack initiation while the extended finite element method (XFEM) is used for the computation of the crack propagation directions and the stress intensity factor range as the indicator of the crack propagation rate. The results show that a nonuniform track bed can reduce fatigue life up to 100 times in comparison with a uniform track bed. The role of inclusion stiffness relative to the background rail steel also is important for fatigue life which depends on the location of the inclusion within the rail. Both types of inclusion affect the direction of the initiated crack propagation. The results of this work are expected to be used for the effective maintenance and scheduling of rail inspections. For more information, contact Dr. Joseph A. Turner at jaturner@unl.edu. Mechanical & Materials Engineering Ph.D. Dissertation Defense Influence of spatial variation of railroad track stiffness and material inclusions on fatigue life Celestin Nkundineza Ph.D. – Mechanical Engineering and Applied Mechanics Advisor: Joseph A. Turner, Ph.D. Friday, November 20, 2015 | 9:30 AM | NH W302