Development of VBI Models with Vehicle Acceleration for Bridge-Vehicle Dynamic Response

摘要

There has been a growing interest to model and analyze the Vehicle-Bridge Interaction (VBI) of intricate vehicles on bridges. VBI analysis is used if the dynamic response of the vehicle in addition to that of the bridge is required. This is particularly sound in case of high-speed trains where the vehicle acceleration is a design criterion for passenger comfort and needs to be well predicted.ud The main objective of this research is to establish efficient numerical procedures within the framework of finite element methods to solve the dynamic response of the VBI systems for vehicles moving with constant velocity or with acceleration. For vehicles with constant velocity, the dynamic condensation method is applied to reduce the vehicle DOFs to the VBI element. A new formulation is proposed for the mass, damping, and stiffness of the VBI element considering new formulation for the contact points.udFor vehicles experiencing acceleration or deceleration, external forces resulting from vehicle horizontal acceleration are numerically formulated in a matrix form as the function of vertical contact forces. By defining a new variable called acceleration parameter, the contact force formula is reformulated. Consequently, a new formulation for the VBI element containing the effect of vehicle acceleration is developed.udThe effect of shear deformation and consistent mass on the vehicle and bridge responses is investigated. The Timoshenko beam element is used to simulate the effect of shear deformation with consistent mass including the effect of rotary mass. Results generally imply that all bridge responses are affected, particularly mid-span acceleration.udA comprehensive parametric study is conducted on the model variables and their effects on the dynamic response of the bridge and the vehicle. The studied parameters include vehicle and bridge damping, frequency parameter, system mass parameter, and a new parameter called vehicle mass parameter. The new VBI element for vehicles experiencing acceleration is studied for three types of vehicle models. Results demonstrate the capability of the developed VBI elements in capturing several dynamic effects when compared to the available models, particularly for high speed vehicles. The new VBI models showed better predictions for the vertical contact forces, vehicle vertical acceleration, and the bridge mid-span deflection.