一个基于优化的有限元模型修正方法

本文提供了一个基于一阶搜索优化的有限元模型修正方法。它只需利用结构模态试验的部分固有频率，就能获得较精确的有限元模型。文中附有某无人机上垂尾有限元模型修正的实例。根据上垂尾前二阶试验的固有频率，采用本文方法，对有限元模型进行了修正。修正后有限元模型的前二阶固有频率与试验值的相对误差在2．35％以内，而第三阶固有频率与试验值的相对误差仅为5．81％。它不仅大大地缩小了用修正前有限元模型算得的固有频率与试验值的相对误差，而且还能较精确地预测无试验结果的高阶固有频率值。

FE Model Updating Method Based on Optimization

A FE model updating method based on first order optimization is presented in the paper.Accurate FE model can be obtained by the method while only several orders of natural frequencies from modal test are needed.An up-perpendicular-tail wing FE model modification of a pilotless aircraft is employed as an example.The natural frequencies of first two orders of the test model are taken into account to modify the FE model and the natural frequency of third order of the test model is predicted by the updated model.The updating results indicate that the percentage errors between the first two natural frequencies of the updated FE model and the results of modal test are less than 2.35%,while the error of the predicted frequency is only 5.81%.Not only could the frequency error between FE model and test model be significantly reduced,but also natural frequencies of higher orders could be predicted accurately by the updated model.