A Vehicle-Bridge Interaction Dynamic System Analysis Method Based on Inter-System Iteration

The vehicle subsystem is modeled by the rigid-body dynamics method,the bridge subsystem is modeled by the FEM,the wheel-rail contact relation is defined by the corresponding assumption in vertical direction and the simplified Kalker creep theory in lateral direction,and track irregularity is regarded as excitation.An inter-system history integral procedure is used to solve the dynamic equilibrium equations of vehicle-bridge interaction system.The bridge subsystem is assumed to have no deformation first to solve vehicle equation to obtain the time histories for vehicle motion and wheel-rail force.The motion status of bridge subsystem can be calculated by acting the obtained wheel-rail force to the bridge.Then the new wheelset exciter is formed by superimposing the time history of deck motion and track irregularity.The next iteration is carried through until the wheel-rail force obtained from the two successive iteration steps meets the convergence condition.The iteration between the vehicle and bridge subsystems within each time step can be avoided in the proposed method and the calculation convergence can be easily promoted by artificially controlling the iteration process,which can improve the calculation efficiency for the dynamic analysis of vehicle-bridge interaction.As a case study,this method together with the traditional time step iterative method are used to analyze the vehicle-bridge interaction dynamic system of a freight train with 30t axle-load running through a continuous rigid frame bridge with the span of(70+3×120+70)m.Results show that the calculation efficiency of the proposed method is higher than that of traditional time step iterative method and number of times for solving equations is only 44%of traditional time step iterative method.