可调连杆机构非线性弹性动力学模型

为了研究可调连杆机构的动态行为，基于有限元方法、Lagrange方程建立了摇杆可调连杆机构的非线性弹性动力学模型。考虑到可调机构构件长度随时间变化，建模时采用变长梁单元将机构结构离散，并计及弹性杆件的轴向和横向弹性位移所引起的附加拉压应变等非线性因素。采用Cear法对非线性动力学方程进行了求解，分析了可调连杆机构的动力学响应特性。结果表明，选择适当的摇杆调节运动规律，可以减小机构构件的弹性变形量，降低最大动应力。

Nonlinear Elastodynamics Model of Adjustable Mechanisms

In order to study the dynamic behavior of adjustable mechanisms, the nonlinear kineto-elastodynamics model for an elastic linkage is established based on FEM, Lagrange dynamic equation, in which the length of the rocker is adjustable. Considering the condition that the length of links of adjustable mechanisms will change with time, the beam element with variable length is applied to discretization of the structure of mechanisms, and the nonlinear factors -the additional tension and compress strains of the beam caused by the displacements of elastic links in axis and cross directions are considered in this model. The solutions of numerical examples are obtained by using Gear method, and the dynamic response of the adjustable mechanisms is analyzed. The result shows that the elastic displacements and the maximum dynamic stress can be reduced by adjusting the length of rocker.