基于虚拟变形方法的结构有限元模型修正

虚拟变形方法是一种快速精确的结构重分析方法。基于静力虚拟变形理论的结构有限元模型修正方法,推导了梁单元影响矩阵和基于虚拟变形的结构位移灵敏度。利用初始结构的静力响应和影响矩阵,就可根据需要对感兴趣的结点响应进行重分析,实现有限元模型的修正,无需修改结构的刚度矩阵;计算位移灵敏度时也与传统算法不同,不需要对整体刚度矩阵求逆,根据虚拟变形方法就可求出相应结点的静力位移灵敏度,提高了模型修正过程中的计算效率。最后分别利用数值仿真和荷载试验数据对一平面框架结构进行了模型修正。

FE MODEL UPDATING OF STRUCTURE BASED ON VIRTUAL DISTORTION METHOD

It was presented a finite element( FE) model updating strategy based on static virtual distortion method( VDM) which belonged to the fast and exact structural reanalysis methods. The influence matrix of beam element and structural displacement sensitivity based on VDM were deduced. According to the static displacements and influence matrix of initial structure,the nodal displacements of interest could be recalculated and then FE model updating could be implemented without modifying structural stiffness matrix. Different from the traditional algorithm requiring stiffness matrix inversion,the corresponding static displacement sensitivity could be directly obtained using VDM,thus enhancing computational efficiency. Finally,FE model updating of a plane frame structure was conducted using numerical simulation results and measured displacements respectively.