热环境下基础激励结构模态参数识别研究

发布时间：2018-05-11 21:30

  本文选题：基础激励 + 模态参数识别　； 参考：《南京航空航天大学》2014年硕士论文

【摘要】：本文分析推导了基础激励加速度传递率与模态参数之间的理论关系,并研究了热环境下基于基础激励加速度传递率的模态参数识别方法。通过热环境下悬臂梁的模态实验验证了该方法的有效性,为热模态参数识别提供一种可行途径。主要工作如下:首先,从振动微分方程入手,推导了多自由度系统基础激励的加速度绝对运动传递率和相对运动传递率,并分析了传递率函数与结构模态参数之间的理论关系。通过悬臂梁算例验证了传递率模型在模态分析中的正确性。其次,基于短时时不变假设,研究了幂基多项式拟合法和时序分析方法在热环境下结构模态参数识别上的应用,通过不同温度时加速度传递率识别出结构模态参数。利用数值算例对两种识别方法的抗噪性进行分析研究,发现时序分析法抗噪性更好。最后,设计完成了热环境下基础激励悬臂梁模态实验。实验包括常温和高温两部分,采用激振器激励和激光非接触测振,分别测量常温、100℃、150℃和200℃时试验件的加速度信号,得到不同温度梁上各点的加速度传递率函数,进而识别出不同温度下悬臂梁的模态参数。实验结果验证了热环境基础激励方式在模态实验中的可行性。
[Abstract]:In this paper, the theoretical relationship between the acceleration transfer rate of the foundation excitation and the modal parameters is analyzed and deduced, and the identification method of the modal parameters based on the acceleration transfer rate of the foundation excitation in the thermal environment is studied. The effectiveness of this method is verified by the modal experiments of cantilever beam in thermal environment, which provides a feasible way to identify the thermal modal parameters. The main work is as follows: first, starting with the vibration differential equation, the absolute and relative motion transfer rates of acceleration excited by foundation excitation of multi-degree-of-freedom systems are derived, and the theoretical relationship between transfer rate function and structural modal parameters is analyzed. The correctness of the transfer rate model in modal analysis is verified by an example of cantilever beam. Secondly, based on the assumption of short-time invariance, the application of power basis polynomial fitting method and time-series analysis method to the identification of structural modal parameters in thermal environment is studied. The structural modal parameters are identified by acceleration transfer rate at different temperatures. Numerical examples are used to analyze the anti-noise performance of the two recognition methods, and it is found that the time series analysis method has better anti-noise performance. Finally, the modal experiment of cantilever beam excited by foundation in thermal environment is designed and completed. The experiment consists of two parts: normal temperature and high temperature. The acceleration signals at 100 鈩，

本文编号：1875702