三维大变形梁系统的动力学建模与仿真*

对三维大变形柔性梁系统的动力学建模和仿真进行了研究。采用绝对节点坐标法描述柔性体的大变形和大位移运动，并由此建立三维大变形柔性梁系统的动力学模型。在此动力学模型基础上，编制动力学仿真软件，实现了对三维大变形柔性梁系统的动力学仿真。给出了两个动力学仿真算例。第一个对柔性单摆自由下落进行了动力学仿真，并与现有文献结果相比较，验证了模型的正确性。第二个对空间柔性双摆的自由下落过程进行了动力学仿真，并将模型计算的结果与使用ADAMS软件计算的结果进行比较。研究结果表明，ADAMS在计算大变形物体动力学时具有局限性，而所得的模型能够有效地对三维大变形柔性梁系统的动力学进行仿真解决这类动力学问题。

Dynamic Modeling and Simulation for Three Dimensional Flexible Beam Systems with Large Deformations

The dynamic modeling and simulation for three dimensional flexible beam systems is studied. The absolute nodal coordinate formulation is used to describe the large deformation and large overall motion of a flexible body. The dynamic model of three dimensional flexible beam systems is established. Based on the said dynamic model a software package to implement the dynamic simulation for three dimensional flexible beam systems with large deformations is compiled. In order to validate the algorithm presented in this paper, two numerical examples are given. One is about the dynamic simulation of a flexible single pendulum dropping freely from one orientation. In this simulation example the results obtained using the proposed model are compared with the results obtained using methods in existing literature, and consequently the correctness of the proposed dynamic model is proven. The other dynamic simulation is carried out for a flexible double pendulum dropping freely from one spatial configuration which can lead to the large deformations. In this simulation of the spatial double pendulum the results obtained using the proposed model are compared with the results obtained using the commercial software ADAMS. The results show that there exists limitation for the software ADAMS to calculate the dynamics of a system with large deformations. Unlike the software ADAMS, the dynamic model obtained can be effectively used in the applications in which the bodies undergo large deformations and large rotations and used to solve these dynamics problems.