作大运动的空间桁架结构动力有限元分析

作大运动的空间桁架，由于运动和变形的耦合将产生动力刚化现象，传统的动力学难以及这种影响，在有限元方法中首次引入单元耦合形函数（阵）将单元弹性位移表示成为单元结点位称的二阶小量形式，利用几何非线性应变－位移关系式，在小变形假设条件下确定单元耦合形函数。根据Ｋａｎｅ方程，运用模态坐标压缩，并通过适当的线性处理，得到了一致线性化的动力学方程，编制空间桁架结构动力刚度有限元分析程序。仿真算例证明理论和算法

Dynamic Finite Element Analysis for Spatial Truss Structures Undergoing Large Overall Motion

Elastic bodies undergoing thehigh-speed and large overall motion can producedynamic stiffening due to the coupling betweenrigid motion and elastic deflection. Traditionaldynamics may hardly involve these terms. A newkind of element coupling shape function meatri-ces is used in finite element method,so that ele-ment elastic displacement is expressed as thesecond order small quantities of element nodedisplacement. The element coupling shape func-tion meatrices are derived by means of geometri-cally nonlinear strain displacement relation un-der small deformation assumption. The Kane'sequations and the modal coordinate reductionmethod are used to establish the consistent lin-earization dynamic equation. A finite elementanalysis program for spatial truss structureswith dynamic stiffening 1s developed. The validi-ty of the theories and algorithms presented inthis paper are verified by the numerical simula-tion sample.