【摘要】：傳統(tǒng)聲學(xué)成像是基于采集聲波對(duì)被探測(cè)散射體散射聲波，反演物體的幾何形貌或確定物體內(nèi)部缺陷，然而這一類傳統(tǒng)聲學(xué)探測(cè)方法受到聲波衍射極限的限制。究其原因，由于聲波在遇到散射體發(fā)生散射時(shí)會(huì)在近場(chǎng)形成凋落波，這一部分聲波會(huì)隨著其傳播距離的增加而呈指數(shù)衰減，由于傳統(tǒng)聲學(xué)成像在遠(yuǎn)場(chǎng)由于凋落波的衰減，從而無(wú)法得到聲場(chǎng)的全部信息。為了克服傳統(tǒng)聲學(xué)成像衍射極限的限制，本文基于超材料的設(shè)計(jì)與等效實(shí)現(xiàn)的原理，提出來(lái)一種實(shí)現(xiàn)零質(zhì)量超材料超分辨成像的實(shí)驗(yàn)設(shè)計(jì)，推導(dǎo)了彎曲波超分辨成像的原理，并利用變換原理，設(shè)計(jì)并實(shí)現(xiàn)了聲隱形通路的效果。本文的主要工作如下 1.實(shí)驗(yàn)實(shí)現(xiàn)了零質(zhì)量超材料超分辨成像。首先建立了一種基于等效零質(zhì)量原理的聲波超材料，并對(duì)這種超材料分別進(jìn)行了超分辨成像的數(shù)值模擬和實(shí)驗(yàn)驗(yàn)證。給出了通過(guò)磁調(diào)控來(lái)實(shí)現(xiàn)對(duì)超分辨成像進(jìn)行主動(dòng)控制的一點(diǎn)實(shí)驗(yàn)結(jié)果，證明了超分辨成像主動(dòng)控制的可行性，為拓展超分辨成像的應(yīng)用做了進(jìn)一步探索。 2.給出了薄板彎曲波推導(dǎo)過(guò)程，并進(jìn)一步推導(dǎo)了彎曲波在特殊薄板，如正交各向異性薄板中的傳播情況。在對(duì)聲波超材料超分辨成像研究的基礎(chǔ)上，，進(jìn)一步探索了彎曲波超材料的超分辨成像的原理，通過(guò)設(shè)計(jì)結(jié)構(gòu)，模擬驗(yàn)證了利用彎曲凋落波成像的可行性，并提出了可以實(shí)現(xiàn)聚焦有助于實(shí)現(xiàn)超分辨成像的結(jié)構(gòu)。 3.基于彈性波方程坐標(biāo)變換不變性，給出了等效質(zhì)量和等效模量都為負(fù)的聲波超材料變換公式，在基于超材料等效原理的基礎(chǔ)上，研究了一種折疊變換結(jié)構(gòu)的超材料，實(shí)現(xiàn)了聲波隱形通路的效果，并設(shè)計(jì)了這種超材料的實(shí)際結(jié)構(gòu)，用3D打印機(jī)制作了這種隱形通路進(jìn)一步做了實(shí)驗(yàn)驗(yàn)證。
[Abstract]:Traditional acoustic imaging is based on the acquisition of acoustic wave scattering acoustic waves, inversion of the geometry of the object or determine the internal defects of the object. However, this kind of traditional acoustic detection method is limited by the acoustic wave diffraction limit. The reason is that acoustic wave will form withered wave in near field when scattering occurs, and this part of acoustic wave will decay exponentially with the increase of propagation distance, because of the attenuation of withered wave in the far field of traditional acoustic imaging. It is impossible to get all the information of the sound field. In order to overcome the limitation of diffraction limit of traditional acoustic imaging, based on the principle of design and equivalent realization of supermaterial, an experimental design for super-resolution imaging of zero-mass supermaterial is proposed, and the principle of super-resolution imaging of curved wave is deduced. Using the principle of transformation, the effect of acoustic stealth path is designed and realized. The main work of this paper is as follows. The zero-mass supermaterial super-resolution imaging is realized experimentally. An acoustic supermaterial based on the principle of equivalent zero mass is established, and the numerical simulation and experimental verification of the super-resolution imaging of the supermaterial are carried out. The experimental results of active control of super-resolution imaging by magnetic control are given. The feasibility of active control of super-resolution imaging is proved. The further exploration is made to expand the application of super-resolution imaging. 2. The derivation process of bending wave of thin plate is given, and the propagation of bending wave in special thin plate, such as orthotropic thin plate, is further deduced. Based on the study of superresolution imaging of acoustic supermaterial, the principle of super-resolution imaging of bent wave supermaterial is further explored. The feasibility of using bending withered wave imaging is verified by designing the structure. The structure of super-resolution imaging can be realized by focusing. 3. Based on the invariance of coordinate transformation of elastic wave equation, the transformation formula of acoustic metamaterials with negative equivalent mass and equivalent modulus is given. Based on the principle of metamaterial equivalence, a kind of supermaterial with folded transformation structure is studied. The effect of acoustic stealth path is realized, and the actual structure of this metamaterial is designed, and the experimental verification is made by using 3D printer.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB34

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 周蕭明;蔡小兵;胡更開;;左手材料設(shè)計(jì)及透明現(xiàn)象研究進(jìn)展[J];力學(xué)進(jìn)展;2007年04期

本文編號(hào)：2316854