Deliberate introduction of acoustic radiation damping using locally resonant materials

许多轻质结构都很僵硬，而且减震效果很弱。这一观察结果也适用于许多乐器和一些水下结构。这些结构的共同之处在于，声辐射衰减的量级可能与其他阻尼机构相似，甚至更高。这项建议旨在研究这种情况，并提供数学公式，允许在纯结构模型中考虑声辐射衰减，尽管实际物理需要耦合的结构声学模型。然而，从数学上讲，结构声学模型可以简化为结构声学模型，其中Schur补表示整个流体行为。本课题对声辐射衰减进行了定量的研究，目的是在不解声辐射问题的情况下，发展一种考虑声辐射衰减的数学模型。除了实际的辐射衰减外，定量估计还包括对声学边界元公式中出现的数值阻尼和可能在高频下变得相关的流体阻尼的研究。非耦合结构模型可将辐射阻尼视为一种模态阻尼或一种粘弹性铺层。最后，将开发和研究利用声辐射减振的结构。

Many lightweight structures are stiff and weakly damped. This observation holds for a number of musical instruments and some submerged structures too. These structures have in common that acoustic radiation damping may be of a similar or even higher magnitude than other damping mechanisms. This proposal is directed to investigate such cases and to provide mathematical formulations which allow to consider acoustic radiation damping in a purely structural model although the actual physics would require a coupled structural acoustic model. However, mathematically, the structural acoustic model can be reduced to a structural one where the Schur complement represents the entire fluid behavior. This project investigates acoustic radiation damping quantitatively and aims at the development of a mathematical model to consider acoustic radiation damping without solution of the acoustic radiation problem. Beside the actual radiation damping, the quantitative estimation includes investigation of numerical damping occurring in acoustic BEM formulations and fluid damping which may become relevant at high frequencies. The uncoupled structural model may consider radiation damping either as a modal damping or as a viscoelastic bedding. Finally, structures which utilize acoustic radiation damping will be developed and investigated.