發(fā)布時間：2018-05-14 19:14

  本文選題：超聲Lamb波 + Chirp信號　； 參考：《北京工業(yè)大學(xué)》2014年碩士論文

【摘要】：復(fù)合材料由于具有強度高、質(zhì)量輕、比剛度大等優(yōu)點而廣泛應(yīng)用在航空航天、風(fēng)電、汽車等各個領(lǐng)域中，在這些領(lǐng)域復(fù)合材料出現(xiàn)任何損傷或者缺陷都有可能給國家財產(chǎn)和人民生命安全帶來巨大威脅，因此發(fā)展一種能夠?qū)?fù)合材料板進(jìn)行快速健康檢測的方法就很有必要。本文采用超聲Lamb波技術(shù)對T300/QY8911復(fù)合材料層合板進(jìn)行了健康檢測技術(shù)研究，結(jié)合線性Chirp信號和橢圓成像定位算法實現(xiàn)了復(fù)合材料板中模擬缺陷的二維成像檢測。本文的具體研究工作如下： （1）研究了線性Chirp信號及其在超聲Lamb波檢測中的應(yīng)用。采用線性Chirp信號作為檢測系統(tǒng)的激勵信號，對其響應(yīng)信號按照控制系統(tǒng)理論進(jìn)行提取可以得到Chirp信號有效帶寬范圍內(nèi)任意頻率點和有效時寬范圍內(nèi)任意周期數(shù)的等效Tone burst響應(yīng)信號。研究表明這一方法提高了檢測效率和信號的信噪比，并且保證了檢測條件的一致性。 （2）提出了三種實現(xiàn)板類結(jié)構(gòu)中Lamb波模態(tài)單一化的方法。首先是雙壓電片激勵法，采用壓電晶片作為激勵傳感器，將兩個性能一致的壓電晶片布置在板上下表面相同位置，給其施加幅值相同且相位也相同的電壓信號可激勵出單一的S0模態(tài)，施加幅值相同但相位相反的電壓信號則可得到單一的A0模態(tài)。第二種是雙壓電片接收法，根據(jù)Lamb波結(jié)構(gòu)特性，，對位于板上下表面相同位置的兩個壓電晶片的接收信號進(jìn)行平均相加或平均相減可分別實現(xiàn)S0模態(tài)或A0模態(tài)的單一化。最后對壓電傳感器進(jìn)行優(yōu)化設(shè)計，壓電晶片添加徑向振動吸收層和阻抗匹配層可在低頻段內(nèi)激勵出單一的A0模態(tài)，將壓電晶片的結(jié)構(gòu)設(shè)計成圓環(huán)狀可激勵出單一的S0模態(tài)。 （3）開展了基于橢圓成像定位的單模態(tài)Lamb波技術(shù)在各向同性板和復(fù)合材料板中的缺陷成像研究。在被測板類結(jié)構(gòu)上布置稀疏壓電傳感器陣列，用環(huán)氧樹脂膠將一鋁鎂合金圓柱粘在復(fù)合材料板上作為模擬缺陷。對傳感器陣列接收到的檢測信號運用橢圓成像定位算法和數(shù)據(jù)融合方法實現(xiàn)了有機玻璃板尤其是T300/QY8911復(fù)合材料層合板上缺陷的二維成像檢測。
[Abstract]:Composite materials are widely used in aerospace, wind power, automobile and other fields because of their advantages of high strength, light weight and high specific stiffness. In these fields, any damage or defect of composite materials may bring great threat to national property and people's life and safety. Therefore, it is necessary to develop a method that can be used to detect composite materials quickly and healthily. In this paper, the ultrasonic Lamb wave technique is used to detect the health of T300/QY8911 composite laminated plates. Combined with linear Chirp signals and elliptical imaging localization algorithm, two-dimensional imaging detection of simulated defects in composite plates is realized. The specific research work of this paper is as follows: The linear Chirp signal and its application in ultrasonic Lamb wave detection are studied. The linear Chirp signal is used as the excitation signal of the detection system. The response signal is extracted according to the control system theory to obtain the equivalent Tone burst response signal at any frequency point in the effective bandwidth range and any period number in the effective time and wide range of the Chirp signal. The results show that this method improves the detection efficiency and signal to noise ratio, and ensures the consistency of detection conditions. In this paper, three methods to realize the mode simplification of Lamb wave in plate structures are proposed. First of all, two piezoelectric wafers with the same performance are arranged in the same position on the upper and lower surface of the plate by using the piezoelectric wafer as the excitation sensor. The single S0 mode can be excited by applying the same amplitude and phase voltage signal, and the single A0 mode can be obtained by applying the same amplitude but opposite phase voltage signal. The second is the bimorph receiving method. According to the structure characteristics of Lamb wave, the received signals of two piezoelectric wafers located at the same position on the upper and lower surface of the plate can be added or subtracted to realize the S0 mode or the A0 mode. Finally, the piezoelectric sensor is optimized. The piezoelectric wafer with radial vibration absorption layer and impedance matching layer can excite a single A0 mode in the low frequency band, and the structure of the piezoelectric wafer can be designed as a ring to excite a single S0 mode. The defect imaging of isotropic and composite plates using single mode Lamb wave technique based on elliptical imaging localization is studied. A sparse piezoelectric sensor array was arranged on the structure of the measured plate, and an aluminum magnesium alloy cylinder was bonded to the composite plate by epoxy resin as a simulation defect. Using elliptical imaging localization algorithm and data fusion method to detect defects on plexiglass plate, especially on T300/QY8911 composite laminates, the detection signals received by sensor array are detected by two-dimensional imaging.
【學(xué)位授予單位】：北京工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TB33;TB553

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 劉增華,何存富,吳斌,王秀彥;利用蘭姆波對板狀結(jié)構(gòu)中隱蔽腐蝕缺陷的檢測[J];實驗力學(xué);2005年02期

本文編號：1889126