Numerical Analysis of Dynamic Stress Response to Moving Load Using Infinite Element and Visco-elastic Boundary

Finite element method provides a competitive way to get access to dynamic stresses subjected to moving loads on the ground. To get reasonable prediction of dynamic stresses using numerical methods, it’s important to choose a proper boundary condition, which can minimize the influence caused by the reflection of the stress waves at the boundary. This paper presents three-dimensional simulations of moving loads of different velocities using two different boundary conditions, infinite element boundary (IEB) and visco-elastic boundary (VEB), based on commercial finite element code ABAQUS. The results show that maximum dynamic stresses are remarkably affected by the velocity of the moving loads. The maximums of dynamic stresses increase slowly with an increasing velocity at first and then rapidly grow when the moving velocity is closer to the Rayleigh wave speed. The comparison of predicted dynamic stresses using these two different boundary conditions and the analytical results shows that at a relative low velocity (less than 70% of the Rayleigh wave speed), both boundary conditions’ results match the numerical solutions well. As the velocity increases (over 70% of the Rayleigh wave speed), the numerical predictions deviate from the analytical results, however, the IEB gives better results because of the simplicity of its coefficients selection.