本文選題：工程結(jié)構(gòu) + 模態(tài)參數(shù)辨識(shí)　； 參考：《重慶大學(xué)》2013年博士論文

【摘要】：工程結(jié)構(gòu)模態(tài)參數(shù)辨識(shí)與損傷識(shí)別技術(shù)作為近20年來(lái)適應(yīng)工程實(shí)際需要而發(fā)展起來(lái)的一門(mén)新學(xué)科，有很強(qiáng)的工程背景，具有重要的實(shí)用價(jià)值。近些年來(lái)，工程結(jié)構(gòu)的健康監(jiān)測(cè)、損傷評(píng)估越來(lái)越受到人們的關(guān)注，，而模態(tài)參數(shù)辨識(shí)和損傷識(shí)別作為其核心技術(shù)和理論基礎(chǔ)已日益成為土木工程領(lǐng)域的研究熱點(diǎn)。由于工程結(jié)構(gòu)體積龐大、約束條件復(fù)雜、材料混雜等原因，對(duì)其進(jìn)行人為激勵(lì)以及對(duì)激勵(lì)信號(hào)進(jìn)行有效測(cè)量是相當(dāng)困難的，因此，基于輸入輸出信號(hào)的傳統(tǒng)模態(tài)參數(shù)識(shí)別理論和方法在工程結(jié)構(gòu)中難以適用。而環(huán)境激勵(lì)下的結(jié)構(gòu)模態(tài)參數(shù)識(shí)別方法，具有無(wú)需施加人為激勵(lì)、費(fèi)用低廉、不影響結(jié)構(gòu)的正常工作、無(wú)需測(cè)量激勵(lì)信號(hào)、更加符合實(shí)際情況等優(yōu)點(diǎn)，在工程界得到了廣泛的應(yīng)用。但現(xiàn)有的模態(tài)參數(shù)辨識(shí)方法和損傷識(shí)別方法在精度、魯棒性、效率以及經(jīng)濟(jì)性能指標(biāo)方面仍存在很多不足，在實(shí)際工程中的應(yīng)用尚處于發(fā)展階段，仍需進(jìn)一步研究和完善。 針對(duì)目前研究中存在的問(wèn)題，本文圍繞環(huán)境激勵(lì)下工程結(jié)構(gòu)模態(tài)參數(shù)辨識(shí)方法和基于模態(tài)參數(shù)靈敏度的損傷識(shí)別方法開(kāi)展研究，歸結(jié)起來(lái)主要內(nèi)容如下： ①計(jì)算三層鋼筋砼框架模型在環(huán)境激勵(lì)下的位移響應(yīng)，利用兩種數(shù)據(jù)預(yù)處理方法（隨機(jī)減量法和NExT法）和ITD法、STD法、復(fù)指數(shù)法、ERA法和ARMA法等5種時(shí)域模態(tài)參數(shù)識(shí)別方法，開(kāi)展了結(jié)構(gòu)模態(tài)參數(shù)辨識(shí)的比較研究。結(jié)果表明：預(yù)處理方法中的NExT法在精度、抗噪性上均優(yōu)于隨機(jī)減量法；五種模態(tài)參數(shù)識(shí)別方法中STD法和ARMA法的對(duì)頻率識(shí)別精度比其它三種方法稍高，在抗噪方面，STD、ERA法、ARMA法的抗噪能力比其它兩種方法稍強(qiáng)，所有方法對(duì)頻率的識(shí)別精度均遠(yuǎn)大于對(duì)阻尼比的識(shí)別精度。 ②結(jié)合隨機(jī)子空間法提出了環(huán)境激勵(lì)下結(jié)構(gòu)模態(tài)參數(shù)識(shí)別的改進(jìn)ITD法、改進(jìn)STD法與改進(jìn)復(fù)指數(shù)法。隨機(jī)子空間法的識(shí)別精度高，其中數(shù)據(jù)的協(xié)方差計(jì)算（矩陣正交投影計(jì)算）可以保留原始數(shù)據(jù)中的所有信息，同時(shí)去除了噪聲，將得到的Toeplitz矩陣（P矩陣）中的數(shù)據(jù)作為ITD法、STD法與復(fù)指數(shù)法的輸入數(shù)據(jù)，這三種方法就不再需要采用隨機(jī)減量法或者自然激勵(lì)技術(shù)法進(jìn)行前處理，從而避免了這兩種前處理方法的不準(zhǔn)確性帶來(lái)的誤差。對(duì)兩跨三層框架模型及一自錨式懸索橋模型的模態(tài)參數(shù)進(jìn)行了識(shí)別，結(jié)果表明：基于協(xié)方差驅(qū)動(dòng)SSI與數(shù)據(jù)驅(qū)動(dòng)SSI的改進(jìn)方法對(duì)比對(duì)應(yīng)隨機(jī)子空間法，在精度未減小的前提下提高了計(jì)算效率，僅用較少的數(shù)據(jù)就可較準(zhǔn)確地識(shí)別出系統(tǒng)的模態(tài)參數(shù)，且識(shí)別精度較高、抗噪性較好；改進(jìn)方法與ITD、STD、復(fù)指數(shù)法相比有精度上的優(yōu)勢(shì)。 ③開(kāi)展了在環(huán)境激勵(lì)下的框架結(jié)構(gòu)模態(tài)辨識(shí)實(shí)驗(yàn)，同時(shí)針對(duì)十二層鋼筋混凝土框架結(jié)構(gòu)的振動(dòng)臺(tái)試驗(yàn)?zāi)Ｐ瓦M(jìn)行了模態(tài)參數(shù)識(shí)別。結(jié)果進(jìn)一步證明了所提出的改進(jìn)方法的正確性、可行性；基于SSI法的改進(jìn)辨識(shí)方法計(jì)算時(shí)間約為SSI法計(jì)算時(shí)間的50%，當(dāng)輸出信號(hào)較多時(shí)，這種優(yōu)勢(shì)更明顯。從而可見(jiàn)，基于SSI法對(duì)ITD、STD、復(fù)指數(shù)法進(jìn)行改進(jìn)后，精度沒(méi)有降低，同時(shí)縮短了計(jì)算時(shí)間，這將為改進(jìn)方法應(yīng)用到結(jié)構(gòu)的實(shí)時(shí)監(jiān)測(cè)提供了可能。 ④在隨機(jī)子空間辨識(shí)法與特征系統(tǒng)實(shí)現(xiàn)算法（ERA）的識(shí)別結(jié)構(gòu)參數(shù)過(guò)程中，確定系統(tǒng)階次是關(guān)鍵。研究了基于奇異值差分譜的去噪原理以及基于奇異值差分譜的分量分離原理。提出了基于奇異值差分譜的隨機(jī)子空間和ERA模型定階方法，通過(guò)該法來(lái)確定模型階次所產(chǎn)生的虛假模態(tài)是最少的，且包含信號(hào)中所有模態(tài)，同時(shí)識(shí)別精度不受影響，并且計(jì)算量最小的階次。通過(guò)試驗(yàn)和數(shù)值分析進(jìn)行結(jié)構(gòu)的模態(tài)識(shí)別，結(jié)果表明該方法是有效的。 ⑤采用相關(guān)系數(shù)法進(jìn)行真實(shí)模態(tài)分量的挑選，剔除低頻虛假模態(tài)分量。采用數(shù)字濾波器對(duì)EMD分解進(jìn)行改進(jìn)，從而克服EMD分解時(shí)出現(xiàn)模態(tài)混疊的情況。針對(duì)經(jīng)過(guò)EMD分解或者數(shù)字濾波后的單頻率分量的信號(hào)，提出了基于奇異值差分譜的去噪的方法，仿真信號(hào)和實(shí)驗(yàn)數(shù)據(jù)分析表明該法去噪效果相當(dāng)明顯。提出了基于奇異值差分譜的模態(tài)分離HHT法，通過(guò)對(duì)仿真信號(hào)和實(shí)驗(yàn)數(shù)據(jù)的模態(tài)辨識(shí)，表明該方法是可行的。 ⑥提出了基于數(shù)字濾波器的STD法、復(fù)指數(shù)法、ARMA法等三種識(shí)別方法，通過(guò)仿真信號(hào)、實(shí)驗(yàn)數(shù)據(jù)處理證明了方法的正確性、可行性，同時(shí)表明該方法能夠有效分離密集模態(tài)，且在識(shí)別過(guò)程中無(wú)需考慮定階問(wèn)題。提出了基于EMD分解的STD法、復(fù)指數(shù)法、ARMA法等三種識(shí)別方法，通過(guò)仿真信號(hào)、實(shí)驗(yàn)數(shù)據(jù)證明了其正確性、可行性，同時(shí)表明該法能夠處理非平穩(wěn)信號(hào)，在識(shí)別過(guò)程中無(wú)需考慮定階問(wèn)題。 ⑦在現(xiàn)有的直接解析法基礎(chǔ)上，本文從三個(gè)方面對(duì)其進(jìn)行了改進(jìn)（包括直接解析法的模型縮聚改進(jìn)，方程迭代解法的改進(jìn)，模態(tài)截尾誤差的改進(jìn)），提出了框架結(jié)構(gòu)損傷識(shí)別的改進(jìn)直接解析法。針對(duì)五層兩跨的框架結(jié)構(gòu)，開(kāi)展了基于改進(jìn)模態(tài)參數(shù)靈敏度法的結(jié)構(gòu)損傷識(shí)別方法研究，結(jié)果表明：在無(wú)噪聲情況下識(shí)別結(jié)果非常正確，而在有噪聲的情況下識(shí)別結(jié)果受到顯著的影響，但在0.1%的噪聲水平下，對(duì)于可接受識(shí)別結(jié)果的正確保證率可以達(dá)到80%以上。成果可為確立工程結(jié)構(gòu)的科學(xué)鑒定系統(tǒng)，制定新的檢測(cè)規(guī)范提供參考。
[Abstract]:In recent years , the traditional modal parameter identification method based on input - output signal has been widely used in engineering structure . However , the traditional modal parameter identification method and the damage identification method have many advantages in engineering structure . However , the existing modal parameter identification method and damage identification method still have many shortcomings in the aspects of accuracy , robustness , efficiency and economic performance .

Aiming at the problems existing in the current research , this paper studies the modal parameter identification method and the damage identification method based on modal parameter sensitivity under the environment excitation , which is summarized as follows :

The results show that the NExT method is superior to the random decrement method in the preprocessing method .
In the five modal parameter identification methods , the frequency recognition accuracy of the STD method is slightly higher than that of the other three methods . In the aspect of anti - noise , the anti - noise ability of the STD , ERA method and the auto - detection method is slightly stronger than that of the other two methods , and the recognition accuracy of all the methods to the frequency is much greater than the recognition accuracy of the damping ratio .

In this paper , the method of improving the structure modal parameters based on the random subspace method is proposed . The method improves the STD method and the improved complex index method . The recognition accuracy of the random subspace method is high , and the data in the data covariance matrix ( matrix orthogonal projection calculation ) can retain all the information in the original data . The results show that the method of the two - span three - layer frame model and the self - anchored suspension bridge model can be used to improve the calculation efficiency . The modal parameters of the system can be accurately identified with less data , and the recognition accuracy is high and the noise - noise is better .
The improved method has the advantage of precision compared with itd , STD and complex exponential method .

( 3 ) The modal identification experiment of frame structure under the environment excitation is carried out , and the modal parameter identification is carried out for the vibration table test model of the twelve - layer reinforced concrete frame structure .
The improved identification method based on the SSI method is about 50 % of the calculation time of the SSI method . This advantage is more obvious when the output signal is much more obvious . It can be seen that the accuracy is not reduced after the improvement of the itd , STD and complex index method based on the SSI method , and the calculation time is shortened , which provides the possibility for the improvement method to be applied to the real - time monitoring of the structure .

In the process of identifying structure parameters of stochastic subspace identification and characteristic system , it is crucial to determine the order of the system . The principle of noise removal based on singular value difference spectrum and component separation principle based on singular value difference spectrum are studied . A stochastic subspace and ERA model order method based on singular value difference spectrum is studied .

The method , simulation signal and experimental data analysis based on singular value difference spectrum are proposed for the signal of single frequency component subjected to EMD decomposition or digital filtering . The method of modal separation based on singular value difference spectrum is proposed , and the modal identification of the simulation signal and experimental data is proposed .

This paper presents three recognition methods based on the digital filter , such as the STD method , the complex exponential method and the auto - index method . The correctness and feasibility of the method are proved through the simulation signal and the experimental data processing .

On the basis of the existing direct analysis method , this paper improves the structure damage identification method based on the improved modal parameter sensitivity method .
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2013
【分類(lèi)號(hào)】：TU317

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4 徐良,江見(jiàn)鯨,過(guò)靜s

本文編號(hào)：1961187