scholarly journals Distribution of generated friction heat at wheel-rail contact during wheel slipping acceleration

2016 ◽  
Vol 20 (suppl. 5) ◽  
pp. 1561-1571
Author(s):  
Milos Milosevic ◽  
Milan Banic ◽  
Dusan Stamenkovic ◽  
Vukasin Pavlovic ◽  
Misa Tomic ◽  
...  

This paper presents an innovative method for determining the distribution of the friction generated heat from the contact of a locomotive wheel and rail, as well as the heat partition factor, during wheel slipping of an accelerating locomotive. The new method combines the finite element analysis simulation and experimental determination of the temperature distribution in a downsized model of a wheel and rail. As a result of a virtual experiment by the finite element analysis, an empirical dependence between the temperature distribution and the heat partition factor was established. The determination of the dependence enabled finding of the exact value of the heat partition factor by the optimization procedure based on matching temperatures obtained by the virtual and real experiment.

Author(s):  
R. Adibi-Asl ◽  
D. O’Kane ◽  
E. Chen

Abstract Thermal ratcheting is required to be checked by most of the piping design codes, specifically the ASME B&PV Code. For cases where the variation of temperature distribution is not uniform, the existing ratchet check methodology for piping is inadequate and therefore the finite element analysis (FEA) is often used to perform ratchet checks. Thermal stratification, in which cold and hot fluid flows are layered in a relatively steady state condition, is a good example of non-linear/non-uniform temperature distribution across the pipe. This paper develops straightforward equations to address thermal stratification in piping. Finite element analysis is used to benchmark the results.


2021 ◽  
pp. 72-85
Author(s):  
L. V Stepanova

In this study coefficients of the multi-parameter Williams power series expansion for the stress field in the vicinity of the central crack in the rectangular plate and in the semi-circular notched disk under bending are obtained by the use of the finite element analysis. In SIMULIA Abaqus, the finite element analysis software, the numerical solutions for these two cracked geometries are found. The rectangular plate with the central crack has the geometry similar to the geometry used in the digital photoelasticity. Numerical simulations of the same cracked specimen as in the experimental photoelasticity method are performed. The numerical solutions obtained are utilized for the determination of the coefficients of the Williams series expansion. The higher-order coefficients are extracted from the finite element method calculations implemented in Simulia Abaqus software package and the outcomes are compared to experimental values. Determination of the coefficients of the terms of this series is performed using the least squares-based regression technique known as the over-deterministic method, for which stresses data obtained numerically in SIMULIA Abaqus software are taken as inputs. The plate with a small central crack has been considered either. This kind of the cracked specimen has been utilized for comparison of coefficients of the Williams series expansion obtained from the finite element analysis with the coefficients known from the theoretical solution based on the complex variable theory in plane elasticity. It is shown that the coefficients of the Williams series expansion match with good accuracy. The higher-order terms in the Williams series expansion for the semi-circular notch disk are found.


1988 ◽  
Vol 16 (2) ◽  
pp. 118-126 ◽  
Author(s):  
S. Parhizgar ◽  
E. M. Weissman ◽  
C. S. Chen

Abstract Accurate determination of stiffness properties of cord-rubber composites is a key to successful finite element analysis of tires. The Halpin-Tsai and similar equations which are used to determine stiffness properties of cord-rubber single plies from the stiffness properties of cord and rubber do not provide adequate accuracy. Determination of these properties from strains directly measured by the Moire technique is more appropriate. In this paper the disadvantages of Halpin-Tsai and similar equations as well as the advantages of the Moire technique for cord-rubber composites are discussed. The stiffness properties obtained using the above different methods are compared. These stiffness properties are then used in the finite element analysis of a two-ply cord-rubber strip. The results of the finite element analyses are compared with experimental data.


2014 ◽  
Vol 602-605 ◽  
pp. 1590-1593
Author(s):  
Han Xin Chen ◽  
Shi Qi Yang

With the continuous development of the ultrasonic detection technology, ultrasonic time of flight diffraction (TOFD) method has been widely applied. The paper investigated the TOFD technique in the detection of natural defects. TOFD detection experiment is established in Lab. The finite element analysis simulation of A-scan signal and ultrasonic TOFD technique in the detection of the longitudinal arrangement of pores defects within the weld specimen transmission are studied. The feasibility and correctness of the finite element analysis model are verified by comparing the experimental signals with the simulation signals.


2019 ◽  
Vol 10 (1) ◽  
pp. 197
Author(s):  
Ah-Der Lin ◽  
Sian Zheng Poon ◽  
Hong-Wei Tu ◽  
Cheng-Yi Chen ◽  
Chao-Ming Hsu

In this study, the optical sphere and the power analyzer were exploited to measure the optical and power parameters for the high-power LED lamps. The results, derived from the experimental data, were used as the power distribution inputs in the finite element analysis (FEA) for the determination of the temperature distribution for the printed circuit board assembly (PCBA) built in the LED lamp. In the finite element analysis, the conjugate heat transfer model was adapted for the calculation of the heat transfer, including thermal conductivity, convection and radiation. Applied on the power chips located on the PCBA, the graphene thermal interface material (TIMs) had been studied for its effects on the temperature distribution. For an accurate simulation about the LED lamp, the model with closed and compact space was built in the analysis. Compared to the experimental data, it showed that the simulation results had a deviation in the range of 3–5% around the main heating source, the light-emitting diodes. It proves the FEA model proposed in this study were well developed for the simulation of the temperature distribution for the high-power LED lamps which have mixed heat transfer mechanisms. The thermal radiation effects by TIMs with graphene were also investigated in this study and proven to be useful for the heat dissipation for the LED lamps.


1997 ◽  
Vol 32 (3) ◽  
pp. 183-191 ◽  
Author(s):  
J Jönsson ◽  
E Svensson ◽  
J T Christensen

A theoretical basis for quasi static determination of wheel—rail interaction forces using strain measures in the foot of the rail is given. Vlasov's theory for thin-walled beams is used in combination with continuous translational and rotational elastic supports based on smoothing out the stiffness of the rail sleepers. The smoothing out of the rotational elastic support has traditionally not been done. The use of this model is validated by the decay lengths of the problem and through finite element analysis. The finite element analysis is performed using discrete sleeper stiffness and Vlasov beam elements. The sensitivity of the measuring technique to parameter variations is illustrated and an example shows the simplicity of the proposed direct measuring technique.


2009 ◽  
Vol 76-78 ◽  
pp. 392-397 ◽  
Author(s):  
Sheng Liu ◽  
Yuan Tong Gu ◽  
Han Huang

A deconvolution method that combines nanoindentation and finite element analysis was developed to determine elastic modulus of thin coating layer in a coating-substrate bilayer system. In this method, the nanoindentation experiments were conducted to obtain the modulus of both the bilayer system and the substrate. The finite element analysis was then applied to deconvolve the elastic modulus of the coating. The results demonstrated that the elastic modulus obtained using the developed method was in good agreement with that reported in literature.


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