How TMM/FTMM simulations help you understand the vibro-acoustic response of multi-layer systems

Ever demanding NVH solutions require a fine understanding of the treatment functioning. This talk will show how TMM/FTMM solution help to get further insight into the energy dissipation mechanisms in various configurations of systems and sound excitation. This type of tool may be used either at the writing of the specification, the design stage or to control the expected noise performance. Based on the expression of the field continuity at each material interface in a multi-layer trim, this approach is computationally efficient, allowing for large parametrical studies. The tool presented here, named AlphaCell, associates an efficient computational core to an intuitive interface. It allows the prediction of the vibro-acoustic response of multi-layer systems to various sound excitations : plane wave at normal incidence (i.e. impedance tube conditions), diffuse sound field, impact sound, rain on the roof and turbulent boundary layer excitation. The discussed examples will comprise vibrating perforated plate based systems, multi-layer trims including visco-elastic layers, studded walls, underlay solutions and glazing subjected to turbulent boundary layer excitation. It will be shown that integrating this type of tool in the design chain allows quicker and more robust NVH product developments.


The Author

Dr. François-Xavier Bécot