Vibroacoustic modeling and design of sandwich and composite lightweight structures with innovative noise control materials

车内噪声是几乎所有航空航天、铁路和机动车辆设计和运行中的重要考虑因素。室内声级主要由主体结构和附属隔音材料的性能和复杂性控制。大型复合板和夹层装饰现在被普遍使用。这样的组件重量轻且耐用，但是它们不能提供足够的隔音或减振。必须降低高振动水平和机舱噪音，以满足新的振动和噪音法规。这需要对其噪声传播机制进行详细和基本的调查，并设计特定的噪声控制处理方法。这是拟议研究计划的主要目标。其目的是通过建模和测试，识别，理解，量化和优化复合材料和夹层结构的传输和耗散机制，并在此基础上开发新的噪声控制声学材料。具体目标是：㈠开发并通过实验验证各种激励（扩散声场、机械、湍流边界层.）下夹层和复合复杂结构（带肋、弯曲、带有装饰支架和声音包的双层壁）的全频谱数值模型; (ii)研究内置阻尼的蜂窝夹层结构的声学和振动性能（粘弹性，毡），（iii）研究和开发创新的多功能材料，在低至中频具有更高的吸收性能;特别是双孔隙材料，智能泡沫，多层与微孔电阻屏和（iv）设计和测试优化的完全代表性的飞机复合材料侧壁与健全的包，夹层装饰板和支架（概念验证）。 拟议的研究解决了这些具有挑战性的问题，使用最先进的计算方法（分析方法，有限元和边界元方法，统计能量分析，混合方法.）的组合。实验工具。后者进行（i）阐明的主要物理现象，（ii）characteretrize研究的结构和acoustc材料，（iii）验证当前和开发的建模工具的预测，以及（iv）展示开发的设计和概念的潜在好处。 拟议的研究是一般性的。它对航空航天、汽车、铁路和建筑等多个行业都很感兴趣。

Interior noise is an important consideration in the design and operation of virtually all aerospace, railways and automotive vehicles. The interior sound level is primarily controlled by the properties and complexity of the main structure and the attached sound proofing materials. Large composite panels and sandwich trims are now commonly used. Such assemblies are lightweight and resistant, but they do not provide sufficient sound isolation or vibration damping. High vibration levels and cabin noise must be reduced in order to meet with new incoming vibration and noise regulations. This requires a detailed and fundamental investigation of their noise transmission mechanisms and the design of specific Noise control treatments. This is the main objective of the proposed research program. It is aimed at identifying, understanding, quantifying and optimizing through modeling and testing, the transmission and dissipation mechanisms through composite and sandwich structures, and on this basis developing new noise control acoustic materials. The specific objectives are: (i) to develop and experimentally validate full frequency spectrum numerical models for sandwich and composite complex structures (ribbed, curved, double walls with trim mounts and sound packages) under various excitations (diffuse acoustic field, mechanical, Turbulent Boundary Layer...); (ii) to investigate the acoustic and vibration performance of Honeycomb sandwich structures with embedded damping (viscoelastic, felt), (iii) to investigate and develop innovative multifunctional materials with higher absorption performance at low to mid frequencies; in particuler double porosity materials, smart foams, multilayers with microporous resistive screens and (iv) to design and test an optimized fully representative aircraft composite sidewalls with sound package, sandwich trim panel and mounts (proof of concept). The proposed research addresses these challenging issues using a combination of state of the art computational methods (Analytical methods, Finite and Boundary Element Methods, Statistical Energy Analysis, Hybrid methods ...) and experimental tools. The latter are undertaken to (i) elucidate the main physical phenomena, (ii) characetrize the studied structures and acoustc materials, (iii) verify the prediction of the current and developed modeling tools, and (iv) demonstrate the potential benefit of the developed design and concepts. The proposed research is generic in nature. It is of interest to several industries such as aerospace, automotive, railway and building.