基于不完备复模态的有限元结构模型修正  

Finite element model updating using incomplete sets of experimental complex modes

作　　者：祁泉泉[1] 辛克贵[1] 

机构地区：[1]清华大学土木工程系,土木工程安全与耐久教育部重点实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2011年第6期750-754,共5页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金资助项目(50878117)

摘　　要：为了解决在不完备复模态条件下有限元结构模型修正结果的不唯一性,在实际结构节点上人为增加已知质量块,利用添加质量块和未添加质量块2组模型的动力试验数据和质量矩阵差,结合差分概念,推导了一种模型修正算法。该算法首先由复模态获取实模态,然后利用差分概念进行模型修正,通过对某6自由度的质量弹簧阻尼系统的模型修正结果表明:本文方法理论上具有完备性,不用迭代优化,可有效解决不完备复模态的有限元模型修正问题,通过把求解未知量的矩阵形式转化成向量形式,可以保证模型的物理特性和降低计算量。A difference model was developed to deal with the non-uniqueness of structural model updates based on incomplete sets of complex modes and natural frequencies.An unique finite element model update is found by known mass blocks to the structure and measuring the structures new complex modal parameters.The normal modes are then generated from the complex modes with the mass/stiffness/damping matrices then updated by the additional information and the normal modes.Model updating of a mass-spring-damping system with 6 degrees of freedom shows that the algorithm is theoretically complete without iterations and is capable of efficiently updating a model with an incomplete set of complex modes.Writing the unknown system matrices in vector forms presents the physical configuration and reduces the computational cost.

关 键 词：模型修正 差分概念 不完备复模态 动力特性 

分 类 号：TU311.3[建筑科学—结构工程]