基于模态综合法的含间隙折叠舵面动态特性分析

基于模态综合法对含间隙折叠舵面的非线性动态特性进行了研究。首先根据折叠舵面的结构特性建立含铰链连接的有限元模型，并采用双协调自由界面模态综合法对折叠舵面的有限元模型进行降阶。其次对不含间隙的折叠舵面进行扫频和模态实验，检验有限元模型及其降阶动力学模型的精度，并基于模型修正得到铰链的等效线性连接刚度。最后将等效线性连接刚度和间隙值进行组合，得到不同间隙下铰链的非线性连接刚度，完成含间隙折叠舵面的非线性动力学模型建立。基于非线性动力学模型对含间隙折叠舵面进行数值扫频，计算结果与实验扫频结果吻合良好，验证了所建立非线性动力学模型的精度及其在含间隙折叠舵面非线性动态特性分析中的可行性。

Dynamic characteristic analysis for a folding fin with freeplay nonlinearities based on mode synthesis method

Nonlinear dynamic characteristics of a folding fin with freeplay nonlinearities are analyzed based on the mode synthesis method. Firstly, the finite element model with hinge connection is established according to the structural characteristics of the folding fin, and subsequently reduced by using the free-interface mode synthesis method. Secondly, sweeping and modal tests are carried out on the folding fin without freeplay nonlinearities to test the accuracy of the finite element model and its reduced substructure model, and the equivalent linear joint stiffness of the hinge is obtained based on the model updating. Finally, the equivalent linear joint stiffness and the freeplay value are combined to obtain the nonlinear joint stiffness of the hinge under different freeplay, and the nonlinear dynamic model of the folding fin with freeplay nonlinearities is established. Numerical simulation of the folding fin with freeplay nonlinearities is carried out based on the nonlinear dynamic model, and the calculated results are in good agreement with their experimental counterparts, which further demonstrate the accuracy of the established nonlinear dynamic model and its feasibility in the analysis of nonlinear dynamic characteristics of folding fins.