平稳随机振动载荷识别的计算机模拟与实验研究

【作者】 李东升；

【导师】 郭杏林；

【作者基本信息】 大连理工大学 ， 工程力学， 2002， 硕士

【摘要】 随着振动问题中系统识别方法的深入，载荷识别问题越来越受到重视。尤其是对于那些无法直接测量载荷的结构，如海洋平台、高大建筑及水工结构等在风浪及地震作用下产生的振动，飞行器在飞行过程中、核反应堆中的部件等的振动。对这些载荷的准确识别，事关人民群众的生命财产安全，有着非常重要的意义。 本文通过计算机模拟不同测点组合的识别情况，将其应用到实际的逆虚拟激励法试验载荷识别过程中。试验结构有阻尼较小结构简单的悬臂梁，和阻尼稍大的有机玻璃框架结构。同时以相干函数和频响函数为依据来调整试验中激振杆，传感器等的安装状态，经多次试验验证取得了较好的识别结果。 本文还尝试运用小量分解法处理识别结果中个别点的异常跳动，并试图将其推广成为广义小量分解法。 试验结果表明运用逆虚拟激励法进行随机振动的载荷识别是可行而有效的，具有良好的应用前景。更多还原

【Abstract】 Loading identification has long been a difficult problem for multi-input multi-output stationary random vibration problems contrary to the fact that system identification is well developed and advanced. In this paper, the Inverse Pseudo Excitation Method (IPEM) is utilized for reconstructing the excitations. Numerical simulations are used to select the optimal combination of reference points, which tested to be very useful in the setting up and processing of experiments so as to obtain reasonable prediction of input loading from selected structural responses, e.g. a few structural acceleration responses. The selected combinations of reference points are then measured on a uniform cantilever beam and a four-story structure made of organic glass subjected to random excitations as well as frequency response functions and coherence coefficients are employed as criteria to adjust the setting status of drive rods, accelerometers etc.Excellent experiment results are achieved from above mentioned tests and generalized epsilon decomposition is tentatively proposed to solve the problem of matrix singularity. It is shown that IPEM combined with computer simulation is a good approach to identify the power spectral density matrix of the applied forces while and before actual experiments proceed.更多还原