James T. Browell
Software Support, Automated Anal. Corp., 2805 S. Industrial, Ste. 100, Ann Arbor, MI 48104
The software needed to develop meshes for acoustic boundary element methods (BEMs) and finite element methods (FEMs) are the ones commercially available for structural finite element codes. However, creating a mesh is only the first step to acoustic model development. The analyst must also consider meshing guidelines required and simplifying assumptions allowed by the various solution methods. The density of acoustic analysis meshes is primarily defined by the geometry of the domain boundary and the maximum frequency of the analysis. Accurately describing the distribution of boundary conditions and coupling interfaces also plays a role. While BEMs have distinct modeling advantages over FEMs, BEMs have specialized modeling requirements. In addition, BEM requires the creation of data recovery meshes to display results, because the surface of the model is not usually the point of interest. Simplifying assumptions are made in acoustic analyses to decrease the time for model development. For example, symmetry is used to simplify a problem. In addition, assumptions are made to simulate fully reflective or pressure release infinite planes, such as highways or ponds, sources are used to represent excitation boundary conditions in the far field, and acoustic damping is considered as surface impedance or complex speed of sound.