含脱层损伤复合材料层合板壳非线性声振建模与机理研究

Fiber-reinforced composite laminated plates and shells are susceptible to delaminations. The presence of delaminations may significantly reduce the structural integrities of the plate and the shell, which may, in turn, results in significant variations in the vibration and acoustic behaviors of the structures. Due to the complexity of composite laminated plate and shell theories, the time-varying nonlinearity of the delaminated interfaces, and the complex coupling effects between the structure and the acoustic field, a general theoretical method for predicting the nonlinear vibro-acoustic behaviors of delaminated composite plates and shells does not exist. An accurate prediction combined with a deep insight into the vibro-acoustic behaviors and mechanisms of delaminated plates and shells becomes a key issue in the low-noise design and evaluation of these structures. On the basis of the previous achievements, a structural domain decomposition method combined with a time-domain Burton-Miller spectral integral formulation is developed for the nonlinear vibro-acoustic analysis of delaminated plates and shells in the time-domain. Experiments on the nonlinear vibration and the vibro-acoustics of delaminated plates and shells are carried out to validate the results of the theoretical analyses. These investigations include: the development of highly accurate shear deformable zig-zag theories for composite laminated plates and shells; the nonlinear vibration modeling and analyses of delaminated plates and shells based on the structural domain decomposition method; the nonlinear vibro-acoustic modeling and analyses of composite laminated plates and shells with delaminations based on the domain decomposition method in conjunction with the time-domain Burton-Miller spectral boundary element method. These investigations are performed in sequence with the objective of developing an efficient computational framework for nonlinear vibration and vibro-acoustic analyses of delaminated composite plates and shells immersed in light or heavy fluid. The physical insights into the mechanism of the nonlinear vibration and vibro-acoustic behaviors of delaminated composite plates and shells are investigated by the numerical methods combined with experiments. The results of the project may provide theoretical and technical supports for the low-noise design and evaluation of composite laminated structures.

纤维增强复合材料板壳易产生脱层损伤，脱层破坏了板壳的完整性并能显著地改变板壳的声振性能。由于层合板壳理论的复杂性、脱层界面的时变非线性以及结构与声场的耦合作用，目前对于脱层板壳的声振耦合问题尚未有可靠的建模方法，准确地预测和识别脱层板壳的声振特性和机理成为复合材料结构低噪声设计和评价的关键技术难题。针对这一问题，在已有研究工作基础上，采用结构区域分解法、时域声学Burton-Miller谱边界元法和试验对脱层板壳的非线性声振建模及机理开展系统地研究。具体内容包括：高精度层合板壳锯齿理论的建立；脱层板壳时域非线性振动区域分解建模与算法实施；基于区域分解-谱边界元法的脱层板壳非线性声振耦合建模与机理分析。研究内容依次开展，旨在形成轻、重流体中含脱层板壳非线性声振耦合问题的高效建模理论与求解体系，揭示脱层板壳的声振特性与机理。项目成果将为复合材料结构的低噪声设计和评价提供有效的理论和技术支持。

复合材料板壳易产生脱层损伤，脱层破坏结构的完整性并能显著地改变复合材料层合板壳的声振性能。准确地预测和识别脱层板壳的声振特性和机理是复合材料结构低噪声设计和评价的难题。本项目建立了能量变分一致的复合材料层合直梁、曲梁、板和壳体广义高阶剪切层合板壳锯齿理论，为复合材料层合结构宽频振动噪声分析提供了高精度结构理论模型；发展了高效的时域区域分解-声学Burton-Miller谱边界元法，解决了时域边界元法长时间历程模拟存在的数值发散问题，为结构-无限域声场耦合非线性动力学研究提供了有效理论分析方法；研究了含脱层损伤纤维增强复合材料板壳、三明治夹层复合材料板壳与流体声场耦合系统的非线性动力学响应特性，揭示了脱层界面接触碰撞、摩擦对复合材料板壳非线性超谐振动及流体声压波形时空畸变的影响规律，阐明了脱层尺寸、位置与结构非线性振动、流体辐射声压之间的映射关系。本项目在AIAA Journal, Journal of Sound and Vibration, Composite Structures等期刊上发表SCI论文13篇，在国内外学术会议上宣读论文6次；指导和培养硕士和博士研究生共4名。在项目成果的支持下，项目负责人入选上海市浦江人才计划（2018年）；获中国振动工程学会青年科技奖（2018年）、教育部自然科学一等奖（排2，2019年）等奖励；获得国家优秀青年科学基金项目（2019年）。项目成果为结构非线性振动噪声分析以及含脱层损伤复合材料结构的振动噪声评价提供了关键理论和方法。