Prediction of sound fields in acoustic cavities coupled to absorptive structures due to vibrating surfaces

In the scope of this contribution a model for the Fluid Structure Interaction (FSI) is presented, where absorptive structures can be considered. A special focus is layed on the interface coupling modes between absorber and fluid. For the simulation of the spatial resolution of the sound field within acoustic cavities techniques based on Finite Element formulations are used. To reduce the number of degrees of freedom a model reduction method, based on a Component Mode Synthesis (CMS), is applied. The cavity boundary conditions, e.g. compound absorbers made of homogenous plates and porous foams, are modeled using Integral Transform Methods (ITM) and appropriate material formulations. Wavenumber dependent impedances are computed for the absorptive structure and used for the coupling with the acoustic cavity adding interface coupling modes for the fluid and applying Hamilton’s principle

Modelling the excitation force of a standard tapping machine on lightweight floor structures

International audienceUp to now the research and development in the field of building acoustics is based mainly on measurements. In consequence the development and optimization of a new building component is a very tedious and expensive task. A considerable reduction of these costs could be achieved, if the optimization relying on measurements would be replaced-at least to some extent-by a computational prediction model. For these models it is necessary to represent not only the component and the adjacent rooms but also the excitation in a suitable way. This paper gives an overview of models for the excitation generated by a standard tapping machine taking into account the interaction between the impacting steel cylinders of the tapping machine and the vibrating surface of the floor

Numerical Models for Violins

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