水下低频宽带强吸声、高阻尼去耦材料对于艇体的隐蔽性具有重大意义。当材料的厚度限制在50mm以内时，传统的水下均质吸声材料可以在较高的频段实现有效吸声，但是难以实现千赫兹频段的有效吸声。虽然含空腔结构、含硬质高密度内核的局域共振结构的引入一定程度上实现了千赫兹频段的吸声，但是空腔结构的抗静水压力较弱；局域共振结构的密度较大，吸声频带较窄。为此，我们组提出了声子玻璃吸声材料的设计构想，实现了千赫兹之上频段的宽带强吸声，但是很难解决千赫兹以内频段的宽带强吸声。此外，声子玻璃材料作为一款新型的消声材料，其吸声性能预报问题一直没有解决，其隔振去耦性能也没有得到很好的研究。为此，本文引入了并联吸声的设计原理，通过多个类穿孔板结构的并联组合来解决千赫兹以内频段的宽带强吸声问题；通过引入改进的水下多孔吸声模型来解决声子玻璃的吸声预报问题；通过对声子玻璃材料样品的振动试验研究，探究了其静力与动力学特性，在此基础上设计了改进型艇用隔振基座并进行了试验研究。

首先是低频吸声问题。水下穿孔吸声结构有微孔型、内插型、孔加橡胶型等，文中首先对影响吸声效果的各个参数进行分析，获得了实现低频强吸声的参数特点。然后使用遗传算法研究了不同的约束条件下，穿孔结构实现低频吸声的组合参数。首先是对于不含橡胶的微孔型与内插型，使用遗传算法搜索确定了多个不同的组合，其可以实现100-1000Hz频段固定频点的强吸声，并对不同的组合进行了对比分析。然后对背腔含橡胶的结构进行搜索获得低频段内不同频点处的强吸声结构，并进行对比分析。

在实现单个结构固定频点强吸声的基础上，本文对穿孔类结构实现宽带吸声的并联结构进行研究，得出了实现并联宽带强吸声的两个条件：背腔隔开与使用欠阻尼单元。在此基础上，进一步研究了背腔中含有橡胶的并联单元的吸声效果，并与未含橡胶的并联单元的吸声效果进行对比分析。最后，利用遗传算法搜索获得了1000Hz以内频段，多种具有宽带强吸声效果的组合结构参数，实现了千赫兹频段内的宽带强吸声结构设计。

针对目前缺乏可用的多孔材料水下吸声预报模型的问题，本文将空气中的多孔声学方法发展到水声应用，建立起空气声与水声材料吸声之间的联系桥梁。本文首先对多孔板泡沫铝在空气中的吸声性能进行测试，利用遗传算法反演获得不同多孔声学模型下的非声学参数，并利用该参数对另一厚度的泡沫铝进行预测，将预测值与实验值对比分析研究反演获得非声学参数准确性。最后选择Padé模型预测泡沫铝含硅油样品的吸声效果，并与泡沫铝中含不同种类聚氨酯材料进行对比分析，验证了预测模型的准确性，一定程度解决了多孔材料水下吸声结构的预报问题。

在水下消声与隔振去耦一体化设计中，本文主要通过试验验证了声子玻璃材料基座具有宽带的减、隔振能力与较强的静力承载能力，有望结合声子玻璃的宽带吸声性能，实现减振、去耦、消声一体化设计。

最后为设计主动可控的新型声呐罩结构，研究了拓扑声波导的特征。文中设计了两种声拓扑结构，一种为六角形单元结构，其可以根据参数的调节实现拓扑带宽的有效调控，相对带宽最大可超过 0.5，显著超过已知的结构；另一种为具有C_2v对称性的长方形声子晶格结构，改变单元旋转角度可以实现结构的拓扑相变，利用相反拓扑相的结构可以构建稳健的拓扑声波导。该波导对缺陷与无序不敏感，为声拓扑绝缘体应用于水声通讯提供了参考。

Underwater low-frequency broadband strong sound absorption and high damping decoupling materials are of great significance for the concealment of the hull. When the thickness of the material is limited to less than 50mm, traditional underwater homogeneous sound-absorbing materials can achieve effective sound absorption in higher frequency bands, but it is difficult to achieve effective sound absorption in the kilohertz frequency band. Although the introduction of a local resonance structure with a cavity structure and a hard high-density core achieves sound absorption in the kilohertz frequency band to a certain extent, the cavity structure has a weaker precipitation resistance, and the density of the local resonance structure is relatively large and the sound absorption band is narrow. To this end, our group proposed the design concept of phononic glass sound-absorbing material, which can achieve broadband strong sound absorption in the frequency band above kHz, but it is difficult to solve the broadband strong sound absorption in the frequency band below kHz. In addition, as a new type of sound-absorbing material, phononic glass material has not been solved the problem of sound absorption performance prediction, and its vibration isolation and decoupling performance has not been well studied. To this end, this paper introduces the design principle of parallel sound absorption, and solves the problem of broadband strong sound absorption within the kilohertz frequency band through the parallel combination of multiple perforated plate-like structures; by introducing an improved underwater porous sound absorption model to solve the problem of phonon The problem of sound absorption prediction of glass; through the vibration test research of phononic glass material samples, its static and dynamic characteristics were explored. On this basis, two types of vibration isolation bases for boats were designed and tested.

The first is the low frequency sound absorption problem. The underwater perforated sound-absorbing structures include microporous, interpolated, and perforated with rubber. The paper first analyzes the parameters that affect the sound absorption effect, and obtains the characteristics of parameters to achieve strong low-frequency sound absorption. Then, the genetic algorithm is used to study the possibility of low-frequency sound absorption of the perforated structure under different constraints. First of all, for the microporous type and the interpolation type without rubber, a genetic algorithm is used to search and determine a number of different combinations, which can achieve strong sound absorption at a fixed frequency in the 100-1000Hz frequency band, and compare the different combinations. analyze. Then, the structure containing rubber in the back cavity is searched to obtain the strong sound absorption structure at different frequency points in the low frequency band, and a comparative analysis is carried out.

On the basis of realizing strong sound absorption at a fixed frequency point of a single structure, we have studied the parallel structure of perforated structures to realize broadband sound absorption, and obtained two conditions for realizing parallel broadband strong sound absorption: the separation of the back cavity and the use of insufficient Damping unit. On this basis, the sound absorption effect of the parallel unit containing rubber in the back cavity was further studied, and the sound absorption effect of the parallel unit without rubber was compared and analyzed. Finally, the genetic algorithm is used to search and obtain a variety of combined structural parameters with broadband strong sound absorption effect in the frequency band below 1000 Hz, and the design of the broadband strong sound absorption structure in the kilohertz frequency band is realized.

Aiming at the problem of lack of available underwater sound absorption prediction models of porous materials, we developed the porous acoustics method in air to the application of underwater acoustics, and established a bridge between airborne sound and sound absorption of underwater acoustic materials. We first tested the sound absorption performance of porous aluminum foam in the air, and obtained the non-acoustic parameters under different porous acoustic models by using genetic algorithm inversion, and used the parameters to predict another thickness of aluminum foam. The accuracy of non-acoustic parameters obtained by inversion is compared with experimental values. Finally, the Padé model was selected to predict the sound absorption effect of the foamed aluminum containing silicone oil samples, and the comparison and analysis with different types of polyurethane materials contained in the foamed aluminum verified the accuracy of the prediction model and solved the problem of porous aluminum to a certain extent. Prediction of underwater sound-absorbing structures of materials.

In the integrated design of underwater noise reduction and vibration isolation and decoupling, this paper mainly through experiments to verify that the phononic glass material base has broadband attenuation, vibration isolation and strong static bearing capacity, which is expected to combine with the phononic glass. Broadband sound absorption performance, realizing the integrated design of vibration reduction, decoupling and noise reduction.

Finally, in order to design a new active and controllable sonar dome structure, the characteristics of topological acoustic waveguides are studied. Two acoustic topological structures are designed in this paper, one is a hexagonal unit structure, which can effectively control the topology bandwidth according to the adjustment of parameters, and its relative bandwidth can exceed 0.5 at most, significantly exceeding the known structure; For the rectangular phonon lattice structure with C_2v symmetry, the topological phase transition of the structure can be achieved by changing the unit rotation angle, and a robust topological acoustic waveguide can be constructed by using the structure of the opposite topological phase. The waveguide is not sensitive to defects and disorder, which provides a reference for the application of acoustic topological insulators in underwater acoustic communication.