基础不均匀沉陷诱发车-桥耦合动力学建模与分析

Dynamic modeling and analysis for a vehicle-bridge coupled system with foundation unequal settlement

探讨基础不均匀沉陷条件下车桥系统的动力学建模问题。利用傅里叶级数将沉降三角坑分解成一系列谐波激励函数,导出由沉降差所致轨道不平顺的力学激扰模型,考虑系统轴向力的影响,应用达朗贝尔原理和振型分解方法建立车-桥系统耦合动力学方程。数值分析了基础沉陷量、桥梁轴向力、车速和结构动力参数等对系统动力学特性的影响。研究表明:沉陷量越大,系统响应的振动幅值越大,过大的局部沉陷量还会伴随着明显的动力冲击,在许多情况下桥梁轴向力对系统横向振动的影响不可忽略。

The dynamic model was presented for a vehicle-bridge coupled system with unequal settlement of foundation. The rail irregularity caused by local subsidence was proposed using a Fourier series model. Dynamic equations were derived for the vehicle-bridge coupled system with longitudinal forces based on D＇Alembert＇s principle and the assumed mode method. The numerical results were obtained and the dynamic responses of the system were discussed due to longitudinal forces, vehicle speed and local subsidence value, respectively. It was shown that there is a big increase in amplitude of vibration or a shock with increase in unequal settlement. In addition, the influence of longitudinal forces on the vibration response of the system can not be neglected in many cases.