Acoustic response behaviour of panels mounted with equipment and its prediction using statistical energy analysis

Responses of non-uniform panels, like equipment panels of spacecraft, are not presently estimated using Statistical Energy Analysis. It is demonstrated that by treating the equipment as separate subsystems, with appropriate coupling loss factors for their connectivity, the response levels of the equipment can be estimated. The coupling loss factors are determined by the wave attenuation caused by the changes in structural properties introduced by the equipment. The estimated responses are valid at locations away from the boundary, in this case interface of the equipment. Information on the vibration levels at the interface of the equipment is necessary, especially to arrive at the random vibration loads of the equipment. A technique is developed to predict the vibration levels at locations at any distance from the interface of the equipment and validated by experiments. The prediction model is based on the interference pattern of the bending waves due to the reflection at the boundaries. It is seen that the existing techniques are suitable in estimating the responses of equipment only if the equipment behaves like mass attached at a point. But the technique developed in this study predicts the responses of the equipment that have large interface area.