本文選題：結(jié)構(gòu)健康監(jiān)測(cè) + 相控陣��； 參考：《南京信息工程大學(xué)》2015年碩士論文

【摘要】：智能結(jié)構(gòu)健康監(jiān)測(cè)利用傳感器技術(shù)及先進(jìn)的信號(hào)處理方法,在結(jié)構(gòu)損傷發(fā)生初期實(shí)時(shí)、在線監(jiān)測(cè)結(jié)構(gòu)健康狀態(tài),及時(shí)準(zhǔn)確的識(shí)別結(jié)構(gòu)中損傷。該方法對(duì)減少災(zāi)難性事故,保證工程安全具有重大意義。超聲相控陣技術(shù)通過調(diào)整陣列中各陣元發(fā)射和接收信號(hào)的時(shí)間延遲,實(shí)現(xiàn)波束的偏轉(zhuǎn)、聚焦等效果。與傳統(tǒng)超聲檢測(cè)技術(shù)相比,超聲相控陣技術(shù)可在不移動(dòng)探頭的情況下,完成全方位、多角度的掃描,提高檢測(cè)精度。本文論述相控陣結(jié)構(gòu)健康監(jiān)測(cè)的相關(guān)理論,說明相控陣檢測(cè)技術(shù)的優(yōu)越性。具體采用8陣元的超聲相控陣陣列檢測(cè)帶損傷的鋁板材料,通過對(duì)壓電陣元發(fā)射與接收過程時(shí)間延遲的控制,完成多方向的聲束掃描,結(jié)合多種信號(hào)處理方式處理采集到的相控陣信號(hào),獲得損傷位置的信息,在圖像中予以顯示。針對(duì)信號(hào)采集過程中,不可避免的會(huì)摻雜工頻干擾信號(hào),結(jié)合巴特沃斯濾波方式、切比雪夫?yàn)V波方式以及橢圓濾波方式,對(duì)信號(hào)做濾波預(yù)處理,在Matlab信號(hào)處理工具箱中調(diào)用數(shù)字濾波器的選擇函數(shù),對(duì)濾波效果進(jìn)行仿真,獲得更加準(zhǔn)確的信號(hào)。在損傷識(shí)別過程中,本文設(shè)計(jì)高效的相控陣檢測(cè)系統(tǒng)采集信號(hào),根據(jù)公式推導(dǎo)及算法分析,獲得發(fā)射、接收過程中陣元的時(shí)間延遲,對(duì)合成信號(hào)的幅值做歸一化處理,將相應(yīng)角度上損傷信號(hào)的幅值用圖像的灰度級(jí)來表示,圖像最亮處即代表損傷。采用超聲相控陣技術(shù)采集得到的信號(hào)也是含有大量噪聲的信號(hào),原始數(shù)據(jù)得到的損傷圖像并不完美,結(jié)合圖像增強(qiáng)方法,對(duì)其進(jìn)行處理,提高圖像的可識(shí)別度。傳統(tǒng)圖像增強(qiáng)的過程中存在對(duì)比度減小和噪聲放大的缺陷,導(dǎo)致圖像細(xì)節(jié)信息丟失,本文將模糊集的方法應(yīng)用其中可以克服該缺陷,得到效果更好的增強(qiáng)后的圖像。傳統(tǒng)采樣過程一般遵循奈奎斯特采樣定理,超聲相控陣技術(shù)采集的信號(hào)量大,給信號(hào)的存儲(chǔ)和傳輸帶來困難。本文采用壓縮感知技術(shù)對(duì)超聲信號(hào)進(jìn)行處理,大大降低存儲(chǔ)和傳輸?shù)男畔⒘俊Ｖ饕ぷ骱w：(1)壓縮感知是基于稀疏信號(hào)的處理方法,利用稀疏變換基,將非稀疏的超聲信號(hào)轉(zhuǎn)換為稀疏信號(hào)；(2)設(shè)計(jì)觀測(cè)矩陣,獲得稀疏向量基；(3)利用多種壓縮感知信號(hào)重構(gòu)算法,重構(gòu)原始信號(hào),經(jīng)重構(gòu)誤差對(duì)比,選取最佳的重構(gòu)算法完成實(shí)驗(yàn)。最后利用壓縮感知處理后的信號(hào),判定損傷位置。
[Abstract]:Smart structure health monitoring uses sensor technology and advanced signal processing methods to monitor structural health in real time at the initial stage of structural damage and identify structural damage in time and accurately. This method is important to reduce disaster accidents and ensure engineering safety. Ultrasonic phased array technology adjusts the array array by adjusting the array array. Compared with the traditional ultrasonic detection technology, the ultrasonic phased array technology can complete the omni-directional, multi angle scan and improve the detection precision. This paper discusses the related theory of phased array structure health monitoring, and explains the phased array detection. The ultrasonic phased array of 8 array elements is used to detect the damaged aluminum plate material. By controlling the time delay of the transmission and receiving process of the piezoelectric element, the multi direction acoustic beam scanning is completed and the signal number of the phased array is processed by a variety of signal processing methods, and the information of the damage position is obtained, and the image is given in the image. In the process of signal acquisition, it is unavoidable to adulterate the power frequency interference signal, combined with Butterworth filtering, Chebyshev filtering and ellipse filtering, the signal is preprocessed by filtering, and the selection function of digital filter is called in the Matlab signal processing toolbox, and the filtering effect is simulated, and more accurate is obtained. In the process of damage identification, this paper designs an efficient phased array detection system to collect signals. According to the formula deduction and algorithm analysis, the time delay of the array element in the process of transmitting and receiving is obtained. The amplitude of the synthetic signal is normalized, and the amplitude of the damaged signal in the corresponding angle is expressed with the gray level of the image, and the image is the most. The signal obtained by the ultrasonic phased array technology is also a signal containing a lot of noise. The damage image obtained by the original data is not perfect, and the image enhancement method is used to process it to improve the recognition of the image. The defects of contrast and noise amplification exist in the traditional image enhancement process. In this paper, the method of fuzzy set can be lost. In this paper, the method of fuzzy set can be applied to overcome the defect and get better image. The traditional sampling process usually follows the Nyquist sampling theorem, the ultrasonic phased array technology has a large signal collection, which brings difficulties to the storage and transmission of the signal. This paper uses compressed sensing technique. The operation deals with ultrasonic signals to greatly reduce the amount of information stored and transmitted. The main work covers: (1) compression perception is based on sparse signal processing, using sparse transform base, converting non sparse ultrasonic signals to sparse signals; (2) design observation matrix, obtain sparse vector base; (3) use a variety of compressed sensing signal weight. The original signal is reconstructed, the reconstruction error is compared, and the best reconstruction algorithm is selected to complete the experiment. Finally, the signal of compressed sensing processing is used to determine the damage position.

【學(xué)位授予單位】：南京信息工程大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN911.7

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 石光明;劉丹華;高大化;劉哲;林杰;王良君;;壓縮感知理論及其研究進(jìn)展[J];電子學(xué)報(bào);2009年05期

2 劉亞新;趙瑞珍;胡紹海;姜春暉;;用于壓縮感知信號(hào)重建的正則化自適應(yīng)匹配追蹤算法[J];電子與信息學(xué)報(bào);2010年11期

3 徐西剛,施克仁,陳以方,洪玉萍,闕開良,香勇;相控陣超聲無損檢測(cè)系統(tǒng)的研制[J];無損檢測(cè);2004年03期

4 王強(qiáng);袁慎芳;邱雷;;基于時(shí)間反轉(zhuǎn)理論的復(fù)合材料螺釘連接失效監(jiān)測(cè)研究[J];宇航學(xué)報(bào);2007年06期

相關(guān)博士學(xué)位論文 前1條

1 孫亞杰;基于超聲相控陣原理的結(jié)構(gòu)健康監(jiān)測(cè)技術(shù)研究[D];南京航空航天大學(xué);2010年

，

本文編號(hào)：1805965