本文選題：基礎(chǔ)激勵(lì) + 模態(tài)參數(shù)識別��； 參考：《南京航空航天大學(xué)》2014年碩士論文

【摘要】：本文分析推導(dǎo)了基礎(chǔ)激勵(lì)加速度傳遞率與模態(tài)參數(shù)之間的理論關(guān)系,并研究了熱環(huán)境下基于基礎(chǔ)激勵(lì)加速度傳遞率的模態(tài)參數(shù)識別方法。通過熱環(huán)境下懸臂梁的模態(tài)實(shí)驗(yàn)驗(yàn)證了該方法的有效性,為熱模態(tài)參數(shù)識別提供一種可行途徑。主要工作如下:首先,從振動(dòng)微分方程入手,推導(dǎo)了多自由度系統(tǒng)基礎(chǔ)激勵(lì)的加速度絕對運(yùn)動(dòng)傳遞率和相對運(yùn)動(dòng)傳遞率,并分析了傳遞率函數(shù)與結(jié)構(gòu)模態(tài)參數(shù)之間的理論關(guān)系。通過懸臂梁算例驗(yàn)證了傳遞率模型在模態(tài)分析中的正確性。其次,基于短時(shí)時(shí)不變假設(shè),研究了冪基多項(xiàng)式擬合法和時(shí)序分析方法在熱環(huán)境下結(jié)構(gòu)模態(tài)參數(shù)識別上的應(yīng)用,通過不同溫度時(shí)加速度傳遞率識別出結(jié)構(gòu)模態(tài)參數(shù)。利用數(shù)值算例對兩種識別方法的抗噪性進(jìn)行分析研究,發(fā)現(xiàn)時(shí)序分析法抗噪性更好。最后,設(shè)計(jì)完成了熱環(huán)境下基礎(chǔ)激勵(lì)懸臂梁模態(tài)實(shí)驗(yàn)。實(shí)驗(yàn)包括常溫和高溫兩部分,采用激振器激勵(lì)和激光非接觸測振,分別測量常溫、100℃、150℃和200℃時(shí)試驗(yàn)件的加速度信號,得到不同溫度梁上各點(diǎn)的加速度傳遞率函數(shù),進(jìn)而識別出不同溫度下懸臂梁的模態(tài)參數(shù)。實(shí)驗(yàn)結(jié)果驗(yàn)證了熱環(huán)境基礎(chǔ)激勵(lì)方式在模態(tài)實(shí)驗(yàn)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，

本文編號：1875702