Alexander Olshevskiy

Three-Dimensional Solid Brick Element Using Slopes in the Absolute Nodal Coordinate Formulation

The present paper contributes to the field of flexible multibody systems dynamics. Two new solid finite elements employing the absolute nodal coordinate formulation are presented. In this formulation, the equations of motion contain a constant mass matrix and a vector of generalized gravity forces, but the vector of elastic forces is highly nonlinear. The proposed solid eight node brick element with 96 degrees of freedom uses translations of nodes and finite slopes as sets of nodal coordinates. The displacement field is interpolated using incomplete cubic polynomials providing the absence of shear locking effect. The use of finite slopes describes the deformed shape of the finite element more exactly and, therefore, minimizes the number of finite elements required for accurate simulations. Accuracy and convergence of the finite element is demonstrated in nonlinear test problems of statics and dynamics. [DOI: 10.1115/1.4024910]

Finite element analysis of railway disc brake considering structural, thermal, and wear phenomena

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.

An improved dynamic model of friction draft gear with a transitional characteristic accounting for housing deformation

ABSTRACT 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.

Wear simulation for the centre plate arrangement of a freight car

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.

Freight cars shunting impacts analysis using an improved dynamic model of friction draft gear

ABSTRACT 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.

A Plate Element With Second-Order Absolute Nodal Coordinate Slopes: Numerical Computation of Shape Functions

In this paper, the procedure of construction of geometrical and structural matrices of plate finite elements employing absolute nodal coordinate formulation (ANCF) is studied. The kinematic and topological properties of an arbitrary plate finite element are described using universal digital code dncm that provides systematic enumeration of finite elements. This code is formed using the element’s dimension d, the number of nodes it possesses n, the number of scalar coordinates per node c, and a multiplier describing the process of transforming a conventional finite element to an ANCF element m. The detailed generation of a new type of triangular plate finite element 2343 using numerical computation of shape functions is discussed in the paper. The new triangular element employs position vectors and slope vectors up to second order mixed-derivative slope vector. A detailed derivation of the equations of motion of the element is provided; the examples of numerical simulation and validation are presented. The features of creating the models and numerical methods as well as results obtained by applying both approaches are discussed in the paper.© 2014 ASME