Structural-acoustic protection for sandwich-composite fuselage

主要目标是开发用于现代飞机的夹层复合材料机身结构的预测工具和附加声学防护。环境限制，包括(质量、大小...)对于飞机的舒适性，将不得不考虑。例如，由于夹层板的刚度和芯层剪切，这些结构可以观察到很高的声学传递率。这些高水平，特别是在低频率下，可能会损害室内舒适度。目前的噪音控制方法需要更重、更厚的声学处理和更多的减振。因此，需要开发更轻、更高效的材料。由于结构-声学问题的耦合特性，需要考虑结构声传播的优化问题。 这个问题具有挑战性。将使用最先进的建模和测试技术。特别是，庞巴迪提供的带有窗户、饰板和地板的真实三明治复合材料机身部分将用作试验台，以验证开发的数值和实验工具，并展示新设计的性能。将实现中低频率的结构-声学性能(复合材料、声学包层、内饰和附件的联合优化)。特别重要的是，将通过数值和实验来研究和优化不同类型的毯子和隔音器底座对室内噪声的影响。复合材料、毯子、内饰和隔振器的设计指南是主要的项目产出。 该项目将受益于与国际专家在EADS Astrium推动的名为“为阿丽亚娜6号开发声学保护”的项目中的合作。由于所研究的结构和目标的相似性(增加声学包层的增强低频性能)以及使用的数值和实验工具，此次合作是一个独特的机会，可以进一步研究两个项目的这些通用方面(模型开发和验证)；增加最先进的技术，以提高我们行业的竞争力；并使我们的学生接触到多国研发协作环境。

The main objective is to develop prediction tools and add-on sound acoustic protection of sandwich-composite fuselage constructions used in modern aircrafts. The environmental constraints, including (mass, size...) for aircraft comfort will have to be considered. For instance, because of the stiffness and core shearing in a sandwich-panel, high acoustic transmission is observed for these constructions. These high levels, especially at low frequencies, can be damaging to interior comfort. Current noise control approaches require heavier, thicker acoustic treatments and more damping. Development of more lightweight and efficient materials is thus needed. Due to the coupled nature of the structural-acoustic problem, the optimization of the acoustic transmission through the structure should be considered. This problem is challenging. State of the art modeling and testing techniques will be used. In particular, a real-life sandwich-composite fuselage section with windows, trim and floor panels, provided by Bombardier, will be used as a test rig to validate the developed numerical and experimental tools and demonstrate the performance of new designs. The structural-acoustic performances (joint optimisation of the composite, acoustic blanket, interior trim and attachment) in low-mid frequencies will be achieved. Of particular importance, the impact on interior noise from different types of blankets and isolator mounts will be investigated and optimized numerically and experimentally. A design guideline for composites, blankets, interior trim and isolators is the main project output. The project will benefit from collaboration with international experts within an EADS Astrium driven project named "Development of an Acoustic protection for Ariane 6". Because of the similarities of the studied structures and targeted objectives (enhanced low frequency performance of added acoustic blanket) and used numerical and experimental tools, this collaboration is a unique opportunity to go further in research on these generic aspects of the two projects (models development and validation); increase the state-of-the-art techniques for our industries competitiveness; and expose our students to multi-national R&D collaborative environments.