多个移动车辆作用下简支梁的动力响应分析

将简支梁桥简化为欧拉-伯努利梁模型,考虑四自由度车辆移动系统与结构表面接触处不平顺产生的随机激励,建立了多个移动车辆振动系统与梁的耦合动力效应模型。在数值算例中,计算了不同模态截断阶数情况下由动力效应产生的挠曲线;讨论了移动速度变化时,在梁上作用不同荷载组合情况下冲击系数的变化规律;并讨论了跨径变化时冲击系数的变化规律;最后比较了在不同等级平整度情况下梁的动弯矩、动剪力的结果。

DYNAMIC ANALYSIS OF A SIMPLY-SUPPORTED BEAM SUBJECTED TO MOVING VEHICLES

The dynamic behavior of bridge structures under moving vehicular loads is studied. The vehicle is modeled as a four-DOF system with linear suspensions and tire flexibility, and the bridge is modeled as a continuous Euler-Bernoulli beam simply supported at both ends. A mathematical model is adopted to describe the roughness of the contact surface between the vehicles and the bridge. The partial differential equation governing coupled vibration of moving vehicles and beam structure is derived. The equation is solved in the time domain by modal analysis and Newmark method. In the numerical examples, the impact coefficient of the bridge is obtained. The shear force and bending moment of the beam are calculated. The dynamic responses of the bridge are simulated with different loads, vehicle speeds, bridge surface roughness, and the span of the beam.