声波超材料设计与应用机理探索
发布时间：2018-11-07 16:03
【摘要】：传统声学成像是基于采集声波对被探测散射体散射声波，反演物体的几何形貌或确定物体内部缺陷，然而这一类传统声学探测方法受到声波衍射极限的限制。究其原因，由于声波在遇到散射体发生散射时会在近场形成凋落波，这一部分声波会随着其传播距离的增加而呈指数衰减，由于传统声学成像在远场由于凋落波的衰减，从而无法得到声场的全部信息。为了克服传统声学成像衍射极限的限制，本文基于超材料的设计与等效实现的原理，提出来一种实现零质量超材料超分辨成像的实验设计，推导了弯曲波超分辨成像的原理，并利用变换原理，设计并实现了声隐形通路的效果。本文的主要工作如下 1.实验实现了零质量超材料超分辨成像。首先建立了一种基于等效零质量原理的声波超材料，并对这种超材料分别进行了超分辨成像的数值模拟和实验验证。给出了通过磁调控来实现对超分辨成像进行主动控制的一点实验结果，证明了超分辨成像主动控制的可行性，为拓展超分辨成像的应用做了进一步探索。 2.给出了薄板弯曲波推导过程，并进一步推导了弯曲波在特殊薄板，如正交各向异性薄板中的传播情况。在对声波超材料超分辨成像研究的基础上，，进一步探索了弯曲波超材料的超分辨成像的原理，通过设计结构，模拟验证了利用弯曲凋落波成像的可行性，并提出了可以实现聚焦有助于实现超分辨成像的结构。 3.基于弹性波方程坐标变换不变性，给出了等效质量和等效模量都为负的声波超材料变换公式，在基于超材料等效原理的基础上，研究了一种折叠变换结构的超材料，实现了声波隐形通路的效果，并设计了这种超材料的实际结构，用3D打印机制作了这种隐形通路进一步做了实验验证。
[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.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34
本文编号：2316854
[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.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34
【参考文献】
相关期刊论文 前1条
1 周萧明;蔡小兵;胡更开;;左手材料设计及透明现象研究进展[J];力学进展;2007年04期
本文编号：2316854
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