On the modeling of thin moving sound sources using a cutFEM approach

While for vibro-acoustic analysis it is often assumed that the source is stationary, in many situations it is moving. Thus, to accurately determine the acoustic response of these systems, a time-varying system has to be solved. This leads to additional challenges, such as how to deal with the varying geometrical configuration and choosing an appropriate time-stepper. Recently, it was shown that cut finite elements (cutFEM) might be a viable solution, since this approach uses a stationary background mesh and cuts the elements wherever the moving source is located, thus omitting remeshing and mesh morphing steps. In this contribution, the approach is extended to also include the possibility to model thin sources (plates/shells), which are a common cause for noise radiation in structures. This is a non-trivial extension, since an immersed thin source leads to a discontinuity in the pressure response among the cut and a local doubling of the elements to capture the pressure on both sides of the cut. This paper describes how to perform numerical integration on the cut elements, how to apply stabilization, and shows a stable time-integration scheme to calculate the solution. It concludes by showing an example of a moving line source.