On the Source of the Systematic Error of the Pressure Measurement Film Applied to Wheel–Rail Normal Contact Measurements

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Jagoba Lekue ◽  
Florian Dörner ◽  
Christian Schindler
Keyword(s):  
Finite Element ◽  
Measurement Error ◽  
Systematic Error ◽  
Pressure Measurement ◽  
Element Model ◽  
Normal Contact ◽  
Failure Pressure ◽  
Research Activities ◽  
Element Failure ◽  
Simulation Results

This paper presents research activities regarding the systematic error of the pressure measurement film when measuring the area of the wheel–rail contact. In particular, an explanation for the different error values shown by the different film types was sought. A finite element model was created based on the assumption that not only the film, but also the microcapsules on top of it alter the results. The performance of the existing film models was enhanced by defining microcapsules with element failure and deletion behaviors. The new model was capable of reproducing the trend shown by the systematic error in the experiments. The simulation results confirmed that the measurement error of a certain film type is not only caused by the film itself, but also depends on the failure pressure and especially the diameter of the capsules.

scholarly journals Calibration of a finite element model of Prescale film for wheel-rail normal contact area measurements

Meccanica ◽  
2021 ◽  
Author(s):  
Jagoba Lekue ◽  
Florian Dörner ◽  
Christian Schindler
Keyword(s):  
Finite Element ◽  
Measurement Error ◽  
Contact Area ◽  
Direct Determination ◽  
Element Model ◽  
Measurement Procedure ◽  
Normal Contact ◽  
Research Activities ◽  
Fundamental Requirement

AbstractThis article presents the latest of a series of research activities aimed to determine the deviation originated when Prescale pressure measurement film is used to measure the size and shape of the wheel-rail contact area. Despite being an attractive solution due to the simplicity of the measurement procedure, it is well known that the contact interaction is altered by the presence of the film. Consequently, characterizing and filtering out the systematic measurement error is a fundamental requirement for accurate quantitative assessments. Nevertheless, the complexity of the wheel-rail contact problem, which lacks an analytical solution, hinders the direct determination of correction values. The approach presented here builds on error corrections for simpler Hertzian geometries to calibrate a film model for further use in the wheel-rail contact scenario. The results highlight the marked dependency of the measurement error on wheel and rail roughness and underline the importance of including the film into finite element models that are validated by comparison with experimental observations.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

scholarly journals Investigation of the Thickness Differential on the Formability of Aluminum Tailor Welded Blanks

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 875
Author(s):  
Jie Wu ◽  
Yuri Hovanski ◽  
Michael Miles
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Dome Height ◽  
Tailor Welded Blanks ◽  
Simulation Results

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.

scholarly journals Reconstruction finite element model of cars

2021 ◽  
Vol 4 (1) ◽  
pp. first
Author(s):  
Lý Hùng Anh ◽  
Nguyễn Phụ Thượng Lưu ◽  
Nguyễn Thiên Phú ◽  
Trần Đình Nhật
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Finite Element Models ◽  
Crash Analysis ◽  
Inertia Moment ◽  
Frontal Crash ◽  
Analysis Center ◽  
Simulation Results ◽  
And Behavior

The experimental method used in a frontal crash of cars costs much time and expense. Therefore, numerical simulation in crashworthiness is widely applied in the world. The completed car models contain a lot of parts which provided complicated structure, especially the rear of car models do not contribute to behavior of frontal crash which usually evaluates injuries of pedestrian or motorcyclist. In order to save time and resources, a simplification of the car models for research simulations is essential with the goal of reducing approximately 50% of car model elements and nodes. This study aims to construct the finite element models of front structures of vehicle based on the original finite element models. Those new car models must be maintained important values such as mass and center of gravity position. By using condition boundaries, inertia moment is kept unchanged on new model. The original car models, which are provided by the National Crash Analysis Center (NCAC), validated by using results from experimental crash tests. The modified (simplistic) vehicle FE models are validated by comparing simulation results with experimental data and simulation results of the original vehicle finite element models. LS-Dyna software provides convenient tools and very strong to modify finite element model. There are six car models reconstructed in this research, including 1 Pick-up, 2 SUV and 3 Sedan. Because car models were not the main object to evaluate in a crash, energy and behavior of frontal part have the most important role. As a result, six simplified car models gave reasonable outcomes and reduced significantly the number of nodes and elements. Therefore, the simulation time is also reduced a lot. Simplified car models can be applied to the upcoming frontal simulations.

ESTABLISHMENT AND APPLICATION OF LOWER LIMB FINITE ELEMENT MODEL BASED ON MUSCLE GROUPS

2018 ◽  
Vol 18 (08) ◽  
pp. 1840024
Author(s):  
MONAN WANG ◽  
RONGPENG LI ◽  
JUNTONG JING
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Finite Element Model ◽  
Lower Limb ◽  
Element Model ◽  
Upper And Lower Bounds ◽  
Three Point Bending ◽  
Living Body ◽  
Prosthetic Socket ◽  
Simulation Results

Living body or corpse could be replaced with the virtual human tissue model for biomechanical experimental study, which effectively avoids the non-reusability, great social controversy, huge costs and difficulty in extracting parameters, and finally, the accurate analysis results are obtained. Unlike the previous lower limb models, the finite element models of hip and thigh were established based on the concept of muscle group in this paper. The cortical bones of hip bone and femur were set as *MAT_PIECEWISE_LINEAR_ PLASTICITY. The material of cancellous bone was set as *MAT_ELASTIC_PLASTIC_ WITH_DAMAGE_FAILURE. The material of articular cartilage was set as *MAT_ISOTROPIC_ELASTIC. The materials of muscle and fat were set as *MAT_VISCOELASTIC. The accuracy of the finite element model was verified by dynamic three-point bending experiment of the thighs. Mechanical simulation was carried out to the stump-prosthetic socket and the comfort of socks by the established model. The simulation results were all between the upper and lower bounds of the experimental results in the dynamic three-point bending experiment of the thighs where the loads were separately applied to one-third of the distal end of thighs and the middle part of thighs. The simulation results of the stump-prosthetic socket example show that the optimal elastic modulus of silicone pad is 2.5[Formula: see text]MPa. Simulation results of socks comfort show that the distribution of stress and deformation of the anterior and posterior thighs is different when the human lower limbs are in stockings. The established simulation model meets the accuracy requirement and can replace the living body or corpse to carry out biomechanical experimental study. The finite element simulation results converge, and the time to complete a finite element calculation is less than or equal to 10[Formula: see text]min.

Numerical Simulation and Process Research for Cylindrical Drawing

2010 ◽  
Vol 20-23 ◽  
pp. 1405-1408 ◽  
Author(s):  
Wei Hua Kuang ◽  
Qun Liu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Process Research ◽  
Die Design ◽  
Drawing Process ◽  
3D Finite Element ◽  
Simulation Results ◽  
Distribution Of Stress

Drawing process is an important technology in shaping products. In the paper, the geometric surfaces of tools and sheet were modeled by Pro/E software, and a 3D finite element model of the cylindrical drawing process was developed by DYNAFORM. Numerical simulation results showed the distribution of stress, strain and thickness. FLD showed no material was in crack area and risk crack area. The drawing process could be successfully completed in one stroke. The simulation results were helpful for the die design.

Electromagnetic Design of a Novel DC Lorentz Motor for Micromanipulation

2012 ◽  
Vol 157-158 ◽  
pp. 106-109
Author(s):  
Xin Yan Qin
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Design Method ◽  
Element Model ◽  
Electromagnetic Design ◽  
Field Coupling ◽  
Model And Simulation ◽  
Simulation Results ◽  
3D Finite Element Method ◽  
Magnetic Field Coupling

In this paper, an electromagnetic design method for a novel DC Lorentz Motor for micromanipulation is described. To optimize permanent magnet (PM) array and minimize the magnetic field coupling among PMs, the distribution of magnetic field and the fluctuation of Lorentz force are obtained by the 3D finite-element method (FEM). Through the electromagnetic analysis, an optimized distribution and shape of PMs are found. Finally, the optimized DC Lorentz motor is manufactured. These simulation results are verified by those of the experiment results, which presents the finite element model and simulation results are reasonable.

Stress Analysis of Laminated Glass under Uniform Lateral Pressure

2011 ◽  
Vol 418-420 ◽  
pp. 50-54
Author(s):  
Shi Hong Pang ◽  
Juan Rong Ma ◽  
Zhen Zhu Ma ◽  
Li Chuang Wang
Keyword(s):  
Finite Element ◽  
Shear Modulus ◽  
Finite Element Model ◽  
Stress Analysis ◽  
Lateral Pressure ◽  
Element Model ◽  
Maximum Principal Stress ◽  
Laminated Glass ◽  
Load Duration ◽  
Simulation Results

The shear modulus of PVB and SGP interlayer is analyzed. With the same conditions of load duration and temperature, the shear modulus of SGP interlayer is about fifteen times than that of PVB interlayer. A finite element model of laminated glass is established in this paper. The simulation results show that the maximum principal stress contours of PVB laminated glass change from a circular to a petal-shaped one and those of SGP laminated glass change form a quadrangular to a square-shaped one when the temperature rises from 20 degrees Celsius to 50 degrees Celsius.

Optimization of Wire Loop Height for a Cavity Down Plastic Pin Grid Array Package

1998 ◽  
Vol 120 (2) ◽  
pp. 194-200 ◽  
Author(s):  
I. Chaudhry ◽  
F. Barez
Keyword(s):  
Finite Element ◽  
Simulation Study ◽  
Thermal Stresses ◽  
Element Model ◽  
Temperature Cycling ◽  
Effect Of Temperature ◽  
Temperature Cycle ◽  
Wire Loop ◽  
Simulation Results ◽  
Test Points

A study has been conducted to resolve wire neck break problem in a cavity-down plastic pin grid array (PPGA) packages with a specific range of parameters when subjected to temperature cycle (−55°C/+125°C). In most cases, a weak or broken neck of the wire was observed after 300 cycles of temperature cycling. The objective of this study is to determine an optimum wire loop height so that the package can pass a 1000 temperature cycles. Results of a simulation study, performed by other researchers, using a finite element model (FEM) were utilized. Their work considered the effect of temperature cycling on PPGA packages identical to those in this report. Several possible factors that can contribute to this failure mechanism were analyzed, and stresses in the wires were evaluated. The simulation results were verified by running an experiment on actual parts. The parts were subjected to temperature cycling, and data was gathered at different test points. The experimental results obtained did concur with simulation results which suggested that the area just above the ball experienced a significant level of thermal stresses, and such stresses could be reduced by determining an optimum loop height.

Sign in / Sign up

Export Citation Format

Share Document