用无偏估计方法计算简支梁的频响函数

Using Unbiased Estimation Method to Calculate Frequency Response Functions of Simply Supported Beams

利用不相关信号的互功率谱多次平均趋于零的性质,推导出多输入多输出频响函数无偏估计算法,用MATLAB语言编制了该无偏估计算法的程序。使用动态信号测试系统进行了简支梁的多点激励和多点响应的振动测试,并利用MATLAB程序对实测信号进行了计算,得到了测试对象的频响函数。利用有限元方法计算测试对象的频响函数,对多输入多输出频响函数无偏估计算法进行了验证。

A multi-input and multi-output unbiased frequency response function （MMUFRF） estimation is put forward based on the feature that the mean of the incorrelate signal CSD （ Cross Spectral Density） tends to zero. The proposed method is realized by MATLAB programming. Two-input and fouroutput test is carried on using the dynamic signal test systems and its MMUFRF is acquired by MATLAB program. Meanwhile, numerical simulation of the frequency response functions is made by means of finite element method. The simulation results show that the proposed MMUFRF can correctly estimate the frequency response functions of real structures.