本文關(guān)鍵詞： 結(jié)構(gòu)健康監(jiān)測 信號相關(guān)系數(shù) Lamb波 無基準(zhǔn) 損傷識別 損傷成像　出處：《南京航空航天大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：本文對航空結(jié)構(gòu)中基于信號相關(guān)系數(shù)的損傷識別方法進(jìn)行了研究。提出了一種有效信號段自提取算法,并在此基礎(chǔ)上分別發(fā)展了基于信號相關(guān)系數(shù)的有基準(zhǔn)和無基準(zhǔn)的損傷識別方法。并探究了裂紋損傷程度的表示方法。首先,本文研究了一種基于信號相關(guān)系數(shù)的有基準(zhǔn)識別及成像方法。先將待檢測結(jié)構(gòu)進(jìn)行區(qū)域分割,分割成若干個子區(qū)域,然后根據(jù)壓電傳感器間的距離和Lamb波的波速,自動計(jì)算并提取出接收傳感器接收到的有效信號段長度。利用提取出的有效信號段計(jì)算基于信號相關(guān)系數(shù)的損傷指標(biāo),最后利用快速成像算法將損傷的位置成像出來。其次,本文研究了一種基于信號相關(guān)系數(shù)的無基準(zhǔn)損傷識別方法。通過在結(jié)構(gòu)上布置一個矩形陣列,形成多個同方向的激勵-接收路徑。利用提取出的有效信號段計(jì)算路徑之間的信號相關(guān)系數(shù)。比較同方向的路徑之間的信號相關(guān)系數(shù)是否為1或者接近1,判斷出不存在損傷的路徑,得到某一方向上的無損信號。將有損信號與無損信號進(jìn)行相減得到損傷點(diǎn)的散射信號。最后通過橢圓定位方法對損傷進(jìn)行定位。最后,本文探究了基于信號相關(guān)系數(shù)的損傷程度表示方法。在結(jié)構(gòu)激勵端的兩側(cè)對稱布置一對傳感器,通過反相激勵激發(fā)出單一的A0波。對裂紋位置不同、尺寸相同,裂紋位置尺寸相同、擴(kuò)展方向不同的兩種情況下進(jìn)行探究。
[Abstract]:In this paper, the damage detection method based on signal correlation coefficient in aeronautical structures is studied, and an effective signal segment self-extraction algorithm is proposed. On the basis of this, the damage identification method with reference and without reference is developed based on signal correlation coefficient, and the expression method of crack damage degree is explored. First of all, In this paper, a method of reference recognition and imaging based on signal correlation coefficient is studied. Firstly, the region of the structure to be detected is divided into several sub-regions, and then according to the distance between piezoelectric sensors and the velocity of Lamb wave, The length of the effective signal segment received by the receiving sensor is automatically calculated and extracted. The damage index based on the signal correlation coefficient is calculated by using the extracted effective signal segment. Finally, the location of the damage is imaged by the fast imaging algorithm. Secondly, In this paper, a nonreference damage detection method based on signal correlation coefficient is studied. Form multiple excitation-receive paths in the same direction. Use the extracted effective signal segments to calculate the signal correlation coefficients between paths. Compare whether the correlation coefficients between paths in the same direction are 1 or close to 1, and determine whether the correlation coefficients between paths in the same direction are 1 or close to 1. There is no damage path, A lossless signal in a certain direction is obtained. The scattering signal of damage point is obtained by subtracting the lossy signal from the lossless signal. Finally, the damage is located by elliptical localization. Finally, In this paper, the method of expression of damage degree based on signal correlation coefficient is studied. A pair of sensors are arranged symmetrically on both sides of the excitation end of the structure, and a single A0 wave is excited by inverse excitation. The crack position is different and the size is the same. The crack location size is the same and the propagation direction is different.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：V267

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本文編號：1519987