基于有效模态质量的有限元建模

Application of Modal Effective Mass for Finite Element Model Construction

介绍一种简单的基于有效模态质量与结构质量的比值∑meff/m来判断有限元模型精确度的方法,给出了基于多自由度系统的理论证明。在通过试验验证了某空间相机及其支架各自有限元模型正确性的前提下,针对二者之间的特殊连接结构采用三种建模方式,分别计算整体结构的有效模态质量和模态频率,其中∑meff/m比值最大的模型所对应的模态频率计算值与试验值最接近,误差在5%之内。有效模态质量是判断有限元模型好坏的重要参数,该方法对一般结构的有限元建模工作有一定的借鉴作用。

A simple method that the value of ∑meff/m was used to determine the accuracy of the finite element model （FEM） was described. The theoretical proof based on multiple degrees of freedom system was proposed. A correct finite element model of a space camera and its support structure was constructed, which was coincident with the experiment results. Three modeling methods to simulate the special connection between the camera and its supported structure were adopted. The modal effective mass and modal frequency were calculated respectively. Compared with the experimental results, it is shown that the model with the largest ratio of ∑meff/mis the most accurate one, and the error is within 5%. Modal effective mass is an important parameter to determine the quality of a FEM, and the method could have a certain reference for the FEM modeling of the ordinary structure.