一种确定模型误差位置的方法

本文首先由解析有限元模型的模态矩阵,得到未测量自由度与已测量自由度模态之间的变换关系,利用该关系对解析模型进行缩聚。然后针对缩聚后的特征方程,利用解析刚度矩阵和质量矩阵以及实测的模态参数确定模型误差位置。模拟结果表明,该方法可行。

DETERMINATION OF THE PHYSICAL LOCATION OF MODEL ERRORS

For model updating purposes the dynamic or static condensation technique are often used to reduce the size of the analytical finite element model due to the size and mesh incompatibility of the experimental and FE models. It is recognized that the physical meaning of the updated model disappears due to model reduction. In this paper the transformation relation between the unmeasured and measured mode shapes is obtained by means of the modal matrix of the analytical FE model. The stiffness and mass matrices are condensed by the relation. Based on the reduced matrix eigen-equation, a method is proposed to locate the physical position of modelling errors in stiffness by using modal test data and the analytical stiffness and mass matrices. The effectiveness of the method is demonstrated through a numerical example.