提取悬挂有弹簧-质量系统桥梁的模态函数,将车辆简化为一个两自由度的移动系统,以桥面不平度功率谱密度为输入,建立车辆与带弹簧-质量系统的桥梁的耦合系统力学模型。结合状态空间理论和演变随机过程的一般理论,研究车-桥耦合演变随机振动的弹簧-质量系统控制。通过数值算例可知:弹簧-质量系统对车辆的随机响应没有影响,而可以降低桥梁的随机响应。最后,探讨了弹簧-质量系统与桥梁质量比、弹簧-质量系统个数对桥梁随机响应的影响。
The random vibration-of a coupled vehicle-bridge system with sprung masses under moving vehicular loads is studied. The mode shapes of the bridge with sprung masses are obtained. The vehicle is modeled as a two-DOF system with linear suspensions and tire flexibility. The power spectral density of the bridge's surface irregularity is taken as input. According to the state space theory and the general evolutionary random processes, the controllable method of analyzing the random response of the coupled system is derived. The numerical studies show that the sprung masses have no effect on the random response of the vehicle, but the random response of the bridge is reduced. The effects of the mass ratio μ, the quantity of sprung masses on the random response of the coupled vehicle-bridge system are discussed.