Dynamic response of double-beam system with nonlinear viscoelastic layer to moving load

¹ Cracow University of Technology, Faculty of Civil Engineering, ul. Warszawska 24, 31-155 Kraków, Poland
² Former student of the Cracow University of Technology, ul. Warszawska 24, 31-155 Kraków, Poland

^* Corresponding author: pkoziol@pk.edu.pl

Abstract

In previous papers, the problem of double-beam system resting on viscoelastic foundation was solved with the assumption of nonlinear foundation stiffness. This multilayer model finds application in railway modelling, where rails are represented by the infinite Euler-Bernoulli beams and sleepers are modelled as a rigid body. In this paper, another assumption is made. The layer connecting two Euler-Bernoulli beams has nonlinear stiffness. This assumption is related to laboratory tests of fastening systems. These tests show that the stiffness of fasteners and rail pads is nonlinear and this factor should be taken into account in detailed analysis of dynamic features. Therefore inclusion of nonlinearity in double-beam system is justified. The physical model presented in this paper consists of two infinitely long beams connected by viscoelastic layer with nonlinear stiffness and resting on viscoelastic foundation. The mathematical model is described by two coupled fourth order partial differential equations of motion with homogeneous boundary conditions. The system is solved by using the Fourier transform and Adomian’s decomposition, combined with the wavelet based approximation of the response using Coiflet filters. The error index for Adomian series is proposed and the approximate solution for vertical vibrations is shown along with computational examples for some systems of parameters.