基于LS-DYNA公路桥梁车桥耦合振动模型

Model of Highway Bridge Subjected to Vehicle-bridge Coupled Vibration Based on LS-DYNA

基于LS-DYNA程序,采用线弹性的橡胶及钢材模拟车轮并定义轮胎内气压,运用转动约束关节和圆柱形约束关节实现车轮转动特性;结合车辆悬架系统动力特性,运用弹簧阻尼单元及梁单元仿真实现悬架动力特性;调整质量单元的大小及分布,实现车体质量分布与实际一致。以某三轴重型车辆为例,建立了用于研究车桥耦合振动响应的精细车辆模型。对比车辆有限元模型的轴载、自振频率理论值与实测值,验证车辆模型的有效性。以某一简支梁桥为例,采用LS-DYNA有限元模拟和MATLAB数值分析移动弹簧-质量-阻尼振动系统,对比研究车辆匀速通过简支梁桥时,各片梁的振动响应。研究结果表明,运用LS-DYNA精细有限元模型能准确分析车桥耦合振动响应,但计算工作量大。

Based on LS-DYNA program, the wheel is simulated with linear elastic material rubber and steel and internal pressure in all tires is defined. The rotation of vehicle wheel is presented through appropriate rotation constraint and cylinder-shaped constraint. The dynamic characteristics of vehicle suspension system are simulated using spring damping elements combing with the dynamic characteristic of the vehicle suspension system. The theoretical quality distribution is well matched with practical through adjusting quality unit size and distribution. A fine finite element vehicle model is established to research the vehicle-bridge coupling vibration response based on a 3-axle heavy-duty vehicle. Comparison of theoretical value and measured value about vehicle axle load, natural frequency of the vehicle FEM is performed to verify the validity of the model. Taking a simply supported beam bridge for example, LS-DYNA finite element and MATLAB are used to simulate and analyse the mass-spring-damp vibration system, and the beams＇ vibration response subjected to vehicle load at constant speed is comparatively researched. The research results show that the feasibility of using LS-DYNA fine model to analyse vehicle-bridge coupling vibration, but the workload of calculation is great.