【摘要】：結(jié)構(gòu)接觸式微裂紋會(huì)導(dǎo)致不規(guī)則的高水平非線性,而且在內(nèi)部傳播的超聲波因接觸聲非線性會(huì)產(chǎn)生如彈性波畸變的非線性聲響應(yīng)。本文研究了結(jié)構(gòu)微裂紋的振動(dòng)聲調(diào)制檢測(cè)技術(shù),基于非線性振子模型研究了振動(dòng)聲調(diào)制的增強(qiáng)作用,重點(diǎn)做了實(shí)驗(yàn)分析研究。 首先,本文分析了非線性振子的研究非線性動(dòng)力學(xué),探討了具有兩個(gè)以上振動(dòng)穩(wěn)態(tài)的結(jié)構(gòu)系統(tǒng)原理,結(jié)合外加磁場(chǎng)分析了非線性作用力的實(shí)現(xiàn),建立非線性結(jié)構(gòu)系統(tǒng)的模型并分析了其動(dòng)力學(xué)規(guī)律。我們?cè)O(shè)計(jì)了雙穩(wěn)和三穩(wěn)懸臂梁非線性振子系統(tǒng),實(shí)驗(yàn)探討了非線性雙穩(wěn)態(tài)系統(tǒng)在參數(shù)d取不同值時(shí),懸臂梁振子末端位移的不同表現(xiàn)。 然后,本文構(gòu)造了三穩(wěn)結(jié)構(gòu)微缺陷檢測(cè)系統(tǒng)模型,該模型能夠依據(jù)非線性動(dòng)力原理擴(kuò)展非共振區(qū)振動(dòng)聲調(diào)制的振動(dòng)激勵(lì)帶。此非線性檢測(cè)模型可以有效利用不同來源的環(huán)境振動(dòng),能有效增強(qiáng)固體材料中不同類型微裂紋的檢測(cè)。調(diào)制指數(shù)值與增加信號(hào)輸入幅值的動(dòng)力學(xué)機(jī)制相吻合。非線性振動(dòng)系統(tǒng)在相當(dāng)小的閾值電壓都可以達(dá)到振動(dòng)聲調(diào)制效果。 另外,本文搭建了雙穩(wěn)結(jié)構(gòu)系統(tǒng)試驗(yàn)?zāi)Ｐ?利用寬帶隨機(jī)振動(dòng)激勵(lì)驗(yàn)證其隨機(jī)共振效應(yīng),實(shí)驗(yàn)分析了該模型的隨機(jī)共振規(guī)律。雙穩(wěn)微裂紋懸臂振子利用隨機(jī)共振機(jī)理拓展了線性壓電振子的共振頻寬、增強(qiáng)了低頻振動(dòng)激勵(lì)下的振動(dòng)響應(yīng),我們從中發(fā)現(xiàn)頻移振動(dòng)聲調(diào)制效應(yīng)。通過將調(diào)制頻率向懸臂振子的共振頻率轉(zhuǎn)換,低頻寬帶激勵(lì)能夠產(chǎn)生振動(dòng)聲調(diào)制效果。這種固有機(jī)制與非線性變化的自然頻率有關(guān)。通過周圍振動(dòng)激勵(lì)的振動(dòng)聲調(diào)制效應(yīng)能夠有效檢測(cè)固體材料的微裂紋。
[Abstract]:The contact micro-crack of the structure can cause irregular high-level nonlinearity, and the ultrasonic wave propagated in the interior will produce a nonlinear sound response such as elastic wave distortion due to the contact acoustic nonlinearity. In this paper, the vibration acoustic modulation detection technology for structural micro-cracks is studied. Based on the nonlinear oscillator model, the enhancement of vibration acoustic modulation is studied, and the emphasis is placed on the experimental analysis. Firstly, this paper analyzes the nonlinear dynamics of the nonlinear oscillator, discusses the principle of structural system with more than two vibrational steady states, and analyzes the realization of the nonlinear force combined with the external magnetic field. The model of nonlinear structural system is established and its dynamic law is analyzed. The bistable and tristable cantilever beam nonlinear oscillator systems are designed. The different behavior of the end displacement of the cantilever beam oscillator when the parameter d is different is discussed experimentally. Then, a tristable structure micro-defect detection system model is constructed, which can extend the vibration excitation band of vibration and acoustic modulation in the non-resonant region according to the nonlinear dynamic principle. This nonlinear detection model can effectively utilize environmental vibration from different sources and can effectively enhance the detection of different types of micro-cracks in solid materials. The modulation exponent value is consistent with the dynamic mechanism of increasing the input amplitude of the signal. The nonlinear vibration system can achieve the vibration and sound modulation effect at a very small threshold voltage. In addition, the experimental model of bistable structure system is set up in this paper. The random resonance effect is verified by wide-band random vibration excitation, and the stochastic resonance rule of the model is analyzed experimentally. By means of stochastic resonance mechanism, a bistable micro-crack cantilever oscillator extends the resonant frequency width of a linear piezoelectric oscillator and enhances the vibration response under low frequency vibration excitation. We find that the acoustic modulation effect of frequency-shifted vibration is found in this paper. By converting the modulation frequency to the resonant frequency of the cantilever oscillator, the low-frequency broadband excitation can produce the vibration-sound modulation effect. This inherent mechanism is related to the natural frequency of nonlinear variation. The vibration acoustic modulation effect of the surrounding vibration excitation can effectively detect the micro-cracks of solid materials.
【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB302.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 周樂;張志文;;無損檢測(cè)及其新技術(shù)[J];重慶工學(xué)院學(xué)報(bào);2006年08期

2 顧鈞元;徐廷學(xué);余仁波;陳海建;;結(jié)構(gòu)健康監(jiān)測(cè)及其關(guān)鍵技術(shù)研究[J];兵工自動(dòng)化;2011年08期

3 王淑蓮;超聲檢測(cè)技術(shù)的發(fā)展與應(yīng)用[J];機(jī)電一體化;1999年05期

4 王建;;疲勞裂紋的危害及原因分析[J];金屬加工(熱加工);2009年14期

5 胡海峰;胡蔦慶;秦國軍;;非線性振動(dòng)聲調(diào)制信號(hào)耦合特征分析[J];機(jī)械工程學(xué)報(bào);2010年23期

6 周正干;劉斯明;;非線性無損檢測(cè)技術(shù)的研究、應(yīng)用和發(fā)展[J];機(jī)械工程學(xué)報(bào);2011年08期

7 王�？�;陳莉;;聲發(fā)射檢測(cè)技術(shù)的原理及應(yīng)用[J];陜西國防工業(yè)職業(yè)技術(shù)學(xué)院學(xué)報(bào);2010年02期

8 冷永剛;王太勇;郭焱;吳振勇;;雙穩(wěn)隨機(jī)共振參數(shù)特性的研究[J];物理學(xué)報(bào);2007年01期

9 陳仲生;楊擁民;;懸臂梁壓電振子寬帶低頻振動(dòng)能量俘獲的隨機(jī)共振機(jī)理研究[J];物理學(xué)報(bào);2011年07期

10 焦敬品;何存富;吳斌;B.W.Drinkwater;S.A.Neild;P.D.Wilcox;;接觸缺陷的振動(dòng)調(diào)制超聲導(dǎo)波檢測(cè)技術(shù)研究[J];聲學(xué)學(xué)報(bào)(中文版);2009年03期

相關(guān)博士學(xué)位論文 前1條

1 胡海峰;板狀金屬結(jié)構(gòu)健康監(jiān)測(cè)的非線性超聲理論與關(guān)鍵技術(shù)研究[D];國防科學(xué)技術(shù)大學(xué);2011年

，

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