【摘要】：近來(lái),在聲物理發(fā)展前沿,波操控技術(shù)為發(fā)展新的減振降噪方法提供了可能。聲學(xué)黑洞結(jié)構(gòu)作為一種典型的波操控結(jié)構(gòu),近來(lái)被廣泛關(guān)注與研究。理想聲學(xué)黑洞結(jié)構(gòu)能達(dá)到波的零反射,并將所有的波動(dòng)能量聚集在結(jié)構(gòu)的尖端位置。然而,實(shí)際加工出的聲學(xué)黑洞結(jié)構(gòu)往往帶有微小的尖端截?cái)?會(huì)破壞結(jié)構(gòu)的零反射特性。在結(jié)構(gòu)尖端粘貼少量阻尼材料,又能減輕這種影響,達(dá)到減振降噪的目的。目前對(duì)聲學(xué)黑洞結(jié)構(gòu)的研究多是從頻域上分析黑洞效應(yīng)的效果,缺乏對(duì)黑洞效應(yīng)時(shí)域產(chǎn)生過(guò)程的研究。此外,關(guān)于尖端截?cái)�、阻尼層等參�?shù)對(duì)黑洞效應(yīng)影響的研究也具有一定的局限性,不利于后期結(jié)構(gòu)的優(yōu)化設(shè)計(jì)。本文將激光超聲技術(shù)引入聲學(xué)黑洞結(jié)構(gòu)的實(shí)驗(yàn)研究中,對(duì)一維聲學(xué)黑洞結(jié)構(gòu)進(jìn)行了詳細(xì)的研究分析。首先,實(shí)現(xiàn)了彎曲波波場(chǎng)可視化,從時(shí)域上展現(xiàn)了彎曲波在一維聲學(xué)黑洞結(jié)構(gòu)上傳播的全過(guò)程。本文設(shè)計(jì)搭建了激光超聲實(shí)驗(yàn)平臺(tái),并提出了虛擬傳感器方法來(lái)改良傳統(tǒng)激光超聲技術(shù),模擬線激勵(lì)信號(hào)。其次,分析了彎曲波特性的變化規(guī)律,并研究了聲學(xué)黑洞效應(yīng)的形成過(guò)程。通過(guò)小波變換、虛擬傳感器等信號(hào)處理方法分析實(shí)驗(yàn)數(shù)據(jù),研究了彎曲波波速、振幅等特性的變化規(guī)律,并探討了聲學(xué)黑洞結(jié)構(gòu)的能量聚集效應(yīng)。最后,確立了基于反射系數(shù)的一維聲學(xué)黑洞效應(yīng)評(píng)價(jià)標(biāo)準(zhǔn),研究了參數(shù)變化對(duì)一維聲學(xué)黑洞效應(yīng)的影響。提出了一種基于波場(chǎng)分離原理計(jì)算結(jié)構(gòu)反射系數(shù)的新方法,討論了尖端截?cái)嗪妥枘釋拥葏?shù)對(duì)聲學(xué)黑洞效應(yīng)的影響,優(yōu)化了聲學(xué)黑洞結(jié)構(gòu)的參數(shù)選擇。
[Abstract]:Recently, in the forefront of the development of acoustic physics, wave manipulation technology provides the possibility for the development of new vibration and noise reduction methods. As a typical wave control structure, acoustical black hole structure has been widely studied recently. The ideal acoustic black hole structure can achieve zero reflection of the wave and gather all the wave energy at the tip of the structure. However, the fabricated acoustical black hole structures often have tiny truncation of the tip, which will destroy the zero reflection characteristics of the structure. A small amount of damping material is attached to the tip of the structure, which can reduce this effect and achieve the purpose of reducing vibration and noise. At present, the study of acoustical black hole structure is mostly to analyze the effect of black hole effect from frequency domain, but lack of research on black hole effect generation process in time domain. In addition, the study of the influence of the parameters such as tip truncation and damping layer on the black hole effect also has some limitations, which is not conducive to the optimization design of the late structure. In this paper, the laser ultrasonic technique is introduced into the experimental study of acoustic black hole structure, and the one-dimensional acoustic black hole structure is analyzed in detail. Firstly, the visualization of the curved wave field is realized, and the whole process of the curved wave propagating on the one-dimensional acoustic black hole structure is shown from the time domain. In this paper, a laser ultrasonic experimental platform is designed and built, and a virtual sensor method is proposed to improve the traditional laser ultrasonic technology to simulate the linear excitation signal. Secondly, the variation of bending wave characteristics is analyzed, and the formation process of acoustical black hole effect is studied. By means of wavelet transform, virtual sensor and other signal processing methods, the experimental data are analyzed, and the variation rules of wave velocity and amplitude are studied, and the energy aggregation effect of acoustic black hole structure is discussed. Finally, the evaluation standard of one-dimensional acoustical black hole effect based on reflection coefficient is established, and the influence of parameter variation on one-dimensional acoustic black hole effect is studied. A new method for calculating the reflection coefficient of a structure based on the principle of wave field separation is proposed. The influence of the parameters such as truncation of the tip and damping layer on the acoustic black hole effect is discussed and the selection of the structural parameters of the acoustic black hole is optimized.
【學(xué)位授予單位】：南京航空航天大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：O42;TN249

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

1 張超;季宏麗;裘進(jìn)浩;吳郁程;;激光超聲檢測(cè)中干涉特征提取算法的研究[J];光學(xué)學(xué)報(bào);2014年07期

2 邊海龍;陳光;;基于短時(shí)傅里葉變換檢測(cè)非平穩(wěn)信號(hào)的頻域內(nèi)插優(yōu)化抗混疊算法[J];儀器儀表學(xué)報(bào);2008年02期

3 曹毅,張榆鋒,毛選珍;小波分析及其在信號(hào)處理中的應(yīng)用[J];現(xiàn)代電子技術(shù);2003年15期

相關(guān)博士學(xué)位論文 前1條

1 高東寶;基于聲學(xué)超材料的新型隔聲技術(shù)研究[D];國(guó)防科學(xué)技術(shù)大學(xué);2013年

相關(guān)碩士學(xué)位論文 前2條

1 吳郁程;基于激光超聲技術(shù)的結(jié)構(gòu)損傷檢測(cè)方法研究[D];南京航空航天大學(xué);2014年

2 李剛;激光超聲技術(shù)及其在金屬無(wú)損檢測(cè)方面的應(yīng)用[D];華中師范大學(xué);2004年

，

本文編號(hào)：2275228