An Explicit Integration Finite Element Method for Impact Noise Generation at a Squat

Abstract

SummaryThis paper presents a full finite element (FE) interaction model of wheel-track to study the wheel-rail impact noise caused by squat. The wheel, the rail and some other track components are modeled with finite elements in three dimensions, where necessary and appropriate. Realistic contact geometry, including geometric irregularity (squat) in the contact surfaces is considered. The integration is performed in the time domain with an explicit central difference scheme. For convergence, the Courant time step condition is enforced, which, together with the detailed modeling of the structural and continuum of the wheel-track system, effectively guarantees that vibration frequency of 10 kHz or higher is reproduced. By making use of the calculated velocities and pressures on the vibrating surfaces, the boundary element method (BEM) based on Helmholtz equation is adopted to transform the vibration of the track into acoustic signal.

Numerical modeling of dynamic frictional rolling contact with an explicit finite element method

“…In addition to the studies of wheel-rail contact solutions [21,22] and contact characteristics [23][24][25][26][27][28], previous studies on wheel-rail interactions with the explicit FEM also include the studies of wheel-rail impact contact (at the rail joint [29][30][31][32][33], squat [34][35][36][37][38][39][40], crossing nose [41][42][43][44][45][46] and crack [47]), studies of flange contact [12,48,49] and track dynamic behavior [39,50,51]. These studies have generally employed algorithm-optimized commercial programs, e.g., ANSYS/LS-DYNA and ABAQUS/Explicit, to efficiently process the large amounts of elements required in the detailed modeling of wheel/track structures and perform time integration with tiny time steps.…”

Numerical and experimental study of wheel-rail impact vibration and noise generated at an insulated rail joint

“…To take account of complex impact contact and high-frequency wheel/rail dynamic effects, this study simulates a wheel-rail impact at a typical IRJ in the Dutch railway network by an explicit FEM, which has been proven to be effective for solving impact contact problems [12][13][14][15] and high-frequency wheel/rail dynamics [16,17]. Performing the integration in the time domain with an explicit central difference scheme, the explicit FEM manages to reproduce high-frequency dynamic effects by detailed modelling of the structure of wheel/track system and employing a small time step.…”

“…This paper first establishes a three-dimensional (3D) FE wheel-IRJ interaction model to simulate impact vibration and noise excited by the target IRJ, and then validates the model against a comprehensive hammer test and a pass-by measurement. Compared to the explicit FE impact models proposed in the previous research [12][13][14][15][16][17], this model is more sophisticated in track dynamics and comprehensively validated. The condition of the target IRJ and wheel-IRJ interaction model are described in Section 2.…”

Developing Noise Maps to Monitor Railway Train Noise at Four Different Keretapi Tanah Melayu (KTM) Stations

“…The noise problem of railway trains has attracted more and more attentions due to the requirements for improving the passengers' comfort and the living environment standard. The noise radiated by the railway system has significantly influenced both passengers inside the trains and the residents along the railway lines [9]. Many researches on railway noise have been conducted since the early 1970s and huge progresses have been made during the past years.…”

“…Many researches on railway noise have been conducted since the early 1970s and huge progresses have been made during the past years. It has been widely accepted that during conventional travelling speeds, the generation of railway noise is mainly because of the wheel and rail frictions [9].…”