Simulating Response of Lightweight Reflectors to Acoustic Tests

Lightweight spacecraft components such as reflectors are very sensitive to acoustic loading, and accurate prediction of peak stresses encountered in an acoustic test is critical to a successful design. A boundary element model (BEM) provides a very accurate means of representing the acoustic input into a finite element model (FEM) of the structure and has proven to be the method of choice for lightweight reflectors. Various aspects of accurate BEM modeling of acoustic input to a FEM of a lightweight reflector will be discussed. This includes choosing the portion of the structure that needs to be modeled to get correct boundary conditions and acoustic input, and also the modeling of the effect of a reverberant chamber on the acoustic response at low frequencies. Predictions will be compared with measured responses for both cases in order to illustrate the critical aspects of this modeling.