基于模态综合技术的结构有限元模型修正

Finite Element Model Updating of Complex Structure Using Component Mode Synthesis Technique

由于结构的动力分析需要大量的计算时间和占用大量的计算机内存,常规的数值迭代计算方法难以实现,提出了基于模态综合技术的模型修正方法。该方法首先得到缩减后结构模型的频率与振型,并将该振型转换为缩减前模型物理坐标下的振型。然后,用缩减后模型的频率和转换后的振型,共同构成模型修正的优化目标函数,进而通过优化求解实现结构的模型修正。该方法既保证了计算精度又提高了模型修正的计算效率,使大型复杂结构的模型修正成为可能。最后,对某吊杆拱桥模型进行了动态测试和模型修正,验证了该算法的有效性。

For real complex structures,model updating by conventional finite element model updating methods is difficult due to the heavy computational burden for the dynamic analysis. Component mode synthesis (CMS) is an effective technique for the dynamic analysis of complex structures. An updating method based on CMS was proposed to improve the efficiency of model updating of real complex structures. A condensed structural model was obtained by the CMS technique,and then an optimal objective function was generated,which consisted of frequencies of the condensed model and the modal shapes transformed from condensed coordinates to initial physical coordinates. The updated model was acquired by solving the optimization problem. The proposed method was validated by updating a scaled suspender arch bridge model using the dynamic measurement data. The result shows that the proposed method is computationally efficient and yet has a high accuracy.