Finite Element Analysis Lab DSMFEM
An improved dynamic model of friction draft gear with a transitional characteristic accounting for housing
Olshevskiy, A., Olshevskiy, A., Kim, C. W., & Yang, H. I.
Received 19 Feb 2017, Accepted 02 Dec 2017, Published online: 29 Dec 2017
A white-box friction draft gear model has been developed. All components of the draft gear are considered. The distinctive feature of the model, as compared to its predecessor, is the transitional characteristic, which accounts for the effect of elastic deformations of the draft gear housing on the position of the friction wedge system components under loading. The adjustment of the model parameters for improved agreement with experimental data is discussed. The new model can be used in the simulation of shunting impacts for single cars and car groups represented by detailed finite-element models. An example of the simulation is presented and compared with experimental data obtained using a shunting hump test stand.
Algorithm of solving contact problems for arbitrary shaped bodies with rough surfaces
using finite element method
Bryansk: Bryansk State Technical University, 2003. — 121 p.
A universal finite element technique for solving contact problems for arbitrary shaped rough bodies has been developed. The parameters describing the stiffness of the rough layer are calculated from simulation of contact of small parts of real bodies with rough surfaces (base models). The base models are generated using the profilometric data from real surfaces, which allows modelling rough surfaces without serious simplifications and assumptions. The data on the rough contact stiffness are applied to real engineering problems. This makes possible to take into account macro-geometry of the object and micro-geometry of its surfaces in contact. The dependencies between the nominal contact pressure and real contact area were investigated. .
Full text of thesis (Russian, pdf, 4.5 Mb)
Analysis of parameters of conformal contact for wheel-center and bandage of an innovative wheel
Vinnik, L., Bourtchak, G., Olshevskiy, A., & Olshevskiy, A.
Volume 265, Issues 9–10, 30 October 2008, Pages 1292-1299
Accepted 24 January 2008, Available online 4 June 2008
The results of the analysis for the innovative design of wheel-sets are presented. This type of wheel-set allows different angular velocities of the bandages with respect to the wheel centers while the gravitational and frictional torsional connection between them remains the same. The results of approximate solution of the tolling contact problem are shown. In particular, the dependencies between the creep in internal contact of the differential rotation wheel-set (DRWS) and driving (or braking) rotational moment during rolling. The results of contact static investigation for differential rotation wheel (DRW) are discussed. The contact problem is solved using finite element method both in 2D and 3D with friction. The conclusion about the appropriateness of using 2D models is drawn.
Finite element simulation of inelastic contact for arbitrarily shaped rough bodies
Olshevskiy A., Yang H. I., Kim C. W.
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science
Volume: 226 issue: 3, page(s): 595-606
Article first published online: August 22, 2011; Issue published: March 1, 2012
Accounting for surface roughness in contact simulation can significantly change the calculated values of contact stresses for many objects. This can be important for high-precision mechanisms where displacements of tens of micrometers are required, such as a machining attachment used to clamp machine elements during processing on high precision machine tools. In this case, even a small deformation changing the shape of asperities can be sufficient to influence the operation of the mechanism. For problems with extensive contact areas and relatively low nominal contact pressures, accounting for surface roughness can change the distribution of the contact stresses and the contact area. Therefore, a contact simulation should be run with minimum set of assumptions. A universal approach to account for surface roughness in the contact of arbitrarily shaped bodies using the finite element method is described. A contact between bodies with nominally flat rough surfaces is considered in order to obtain diagrams of normal and tangential contact stiffness. An elastic–plastic pattern of material deformation is determined using yield theory. The distribution of the contact area during load growth is discussed. The application of contact stiffness diagrams in contact simulation for rough bodies is described, and some numerical results are given.
Finite element analysis of railway disc brake considering structural, thermal, and wear phenomena
Olshevskiy, A., Olshevskiy, A., Berdnikov, O., & Kim, C. W.
Volume: 226 issue: 7, page(s): 1845-1860
Article first published online: November 15, 2011; Issue published: July 1, 2012
The purpose of this research is to identify the thermomechanical factors to be considered in simulation of the braking process, calculation of the distribution of the contact pressure, and temperature and obtain wear patterns for the disc brake system in operation. The factors affecting the temperature distribution and stress–strain state of disc brakes in railway vehicles are analyzed. The mutual influence of the thermal problem and contact problem was considered. The results of the numerical simulations for the finite element models can be used in optimizing the disc brake design in order to reduce wear and provide higher reliability of the braking system.
Wear simulation for the centre plate arrangement of a freight car
Olshevskiy, A., Kim, C. W., Yang, H. I., & Olshevskiy, A.
Volume: 53 issue: 6, page(s): 856-876
Received 07 Oct 2014, Accepted 22 Feb 2015, Published online: 02 Apr 2015
The bodies of many railway freight cars in many countries of the world are coupled to the running gear by means of a body centre plate that makes a friction pair with a centre bowl. During motion, the bogie is rotated and moved with respect to the car body. This leads to wear on the contact surfaces. Lubrication is inexpedient in this case because the friction forces damp the vibrations (so-called bogie hunting) during motion. Usually, centre plates exhibit noticeable wear after two years of operation. Reducing wear requires knowing details of the wear process which, in turn, requires computer simulation of freight car motion for an operation period of 10–15 years. The purpose of this paper is to develop a universal method for wear simulation of friction pairs that could be used, in particular, for the centre plate of a freight car.
Efficient three-stage approach to fatigue life assessment for transport machines in the context of stilt
Olshevskiy, A., Kulinichev, N., Olshevskiy, A., Kim, C. W., & Yang, H. I.
Volume 81, November 2017, Pages 10-30
Received 25 October 2016, Revised 3 June 2017, Accepted 14 June 2017, Available online 16 June 2017
In this study an efficient three-stage method for fatigue life assessment combining multibody dynamic analysis and finite element method is considered in the context of investigating the performance of a serial stilt sprayer. The proposed approach enables accurate simulation of dynamics for a vehicle subjected to real loads and finite element analysis for detailed models and does not lead to high computational complexity of the problem. The two-level finite element model is used for reducing computational costs of the analysis. The fatigue life of the stilt sprayer chassis frame is assessed on the basis of Palmgren–Miner damage theory. All stages of the study are described in detail. The research may be useful for mechanical engineers and specialists in strength and fatigue calculations.
Freight cars shunting impacts analysis using an improved dynamic model of friction draft gear
Olshevskiy, A., Olshevskiy, A., Kim, C. W., & Yang, H. I.
Received 24 Feb 2017, Accepted 02 Dec 2017, Published online: 27 Dec 2017
In this study, simulations of shunting impacts for groups of freight cars that include up to six cars are considered. The simulation technique employs a white-box improved dynamic model of friction draft gear considering all its components and detailed finite element models of the freight cars. The key differences between the one-to-one shunting impact and the impact of long groups of cars in terms of features of the draft gear deflections and the coupler force time history are discussed. We present an example of dynamic finite element analysis for the car body using the coupler force time history obtained from the shunting impact simulation.