研究具有大范围运动和非线性变形的空间柔性梁的有限元动力学建模.首先在精确描述空间柔性梁的非线性变形的基础上,采用有限元方法对梁结构进行离散,导出其动能、势能及外力对应的广义力,然后利用Lagrange方程建立了空间柔性梁的精确动力学方程.该方程在原有一次耦合模型的基础上,增加了新的表征纵向、横向、侧向弯曲变形,以及扭转变形的耦合项,同时包含了变形运动与大范围运动之间的相互耦合项.本建模方法和所得结论可为以后空间柔性梁的动力学特性分析作以参考.
In this paper, the dynamic modeling theory of a spatial flexible beam, which und ergoes large overall motion and nonlinear deformation, is investigated. As we know, in spacecraft and space station, there are a lot of flexible appendices so the dynamic modeling of a flexible beam is essential. Yet the existing models, in our opinion, lack several important coupling terms. This paper supplies these important coupling terms. Based on the new approach of deformation of fully geometrically nonlinear beam model developed,the finite element method is used for the system discretization and the coupling dynamic equations of flexible beam are obtained by Lagrange’s equations. The complete expression of stiffness matrix and all coupling terms are included in the dynamic equations. The second order coupling terms between rigid large overall motion, arc length stretch, lateral flexible deformation kinematics and torsional deformation terms are included in the present exact coupling model to expand the theory of one-order coupling model. The dynamicmodeling method in this paper is of theoretical significance and has reference value for the rigid-flexible coupling system dynamic investigation .