移动荷载下离散粘弹性点支承长梁的有限元分析

Finite element analysis of long beam on discrete viscoelastic supports subjected to moving loads

研究了单个和多个移动荷载作用下离散粘弹性点支承长梁的动力响应.把长梁、离散的粘弹性支座和移动荷载视为一个系统,利用弹性系统动力学总势能不变值原理及形成矩阵的"对号入座"法则建立该系统的振动方程组,用Wilsonθ法求解该振动方程组,得到梁的位移时程曲线.举例分析了梁的抗弯刚度、支座的粘弹性特性及移动荷载的速度对梁动力响应的影响.计算结果表明:增大支承点的弹簧刚度、阻尼系数及梁的抗弯刚度都有利于减小梁的动力响应;随荷载速度的提高,梁的动力响应有所增大.图7,表1,参16.

Dynamic responses of long beam on discrete viscoelastic supports subjected to single and multiple moving loads are studied. Long beam,discrete viscoelastic supports and moving loads are considered as a system.vibration equations of the system can be formulated by using the principle of stationary total potential energy in elastic system dynamics and the 'Setinrightposition' rule for formulating matrixes.The equations are solved by Wilson θmethod;and the displacement time histories of the beam are obtained. Numerical examples are presented and the influences of bending stiffness of beam,of characteristic of viscoelastic supports and of the speed of moving loads on dynamic responses of beam are analyzed.Calculation results show:the increase either of spring stiffness of support,or of damping coefficient of support,or of the bending stiffness of beam each leads to the decrease of dynamic responses of beam;with the increase of the speed of moving loads,the dynamic response of beam also increase.7figs.,1tab.,16refs.