Improvements to Vehicle Interior Noise Simulation

Simulation of interior vehicle structure-borne noise is typically performed with coupled acoustic-structure finite element models. The structure body mesh and acoustic cavity mesh are usually non-conformal, hence finite element solvers use coupling algorithms based on projected areas to develop the connection between the fluid pressure degree of freedom and the structure displacement degrees of freedom. Robust coupling algorithms need to account for various challenges such as separation and penetration of the meshes, openings in the structure mesh, and overlapping panels in the structure mesh. A new coupling algorithm that uses precise area projections addresses these issues and has been implemented in an FE solver code base. The robustness and accuracy solution is demonstrated by comparison to existing methods. Another challenge with acoustic simulation is to join dissimilar acoustic meshes. This commonly occurs with seat volumes meshed as dense fluid that need to be joined to the true air volume. Typically this has been done with manual constraint element connections which are not only difficult but are also error prone. An acoustic “glue” coupling has been developed that allows coupling acoustic mesh faces using a simple and very accurate procedure. Examples of this application are demonstrated as well.