基础激励下结构模态参数识别

MODAL PARAMETER IDENTIFICATION OF STRUCTURE UNDER BASE EXCITATION

研究了基础激励的特点,给出了利用振动台进行试件模态参数识别的方法。由经过噪声剔除的激励与实测响应的傅里叶变换,构造试件的控制方程,再用最小二乘法求得试件的模态参数。文中对上述方法的实施、有限元模型的建立、质量阵的动态修改、夹具设计、模态转换等有关问题,进行了比较全面、系统的讨论,给出了相应的解决方案。仿真计算与实物试验结果,验证了所提方法的有效性、可行性及其良好的精度。

After an investigation of characteristics of base excitation, a method of modal parameter identification of structure under based vibration shaker excitation was presented. The modal parameters of the specimen were obtained from governing equation constituted with Fourier Transforms of excitation and measured response, which have got rid of noise contamination,of the specimen by means of Least Square Method. A detailed discussion and systematic study for execution of the method, modeling of finite element and dynamic modification of mass matrix, fixture design and mode transformation were also carried out. The appropriate measures were taken to some knotty problems. Results of digital simulation and specimen test demonstrated the effectiveness, feasibility and fine accuracy of the proposed method.