Time Domain Finite Element Analysis for Coupled Rooms Separated by an Elastic Plate

摘要

The paper analyzes a sophisticated vibro-acoustic problem, which is unavoidable when one deals with structure and fluid interactions. The complexity encountered for solving the problem arises due to coupling equations generated from involved parts. Here, to solve the problem numerically, a Time Domain Finite Element Method (TDFEM) combined with the Newmark-β integration method is presented. The method has been successfully applied to predict the sound field in such a large acoustical space, yet a similar outcome in vibroacoustic problems remains obscure. Therefore, the paper aims to extend the method to a more complicated vibro-acoustic area and to consequently evaluate the suitability of the method. To check the accuracy of TDFEM, the room transfer function obtained from Fourier transformed results is compared with those of direct frequency analysis in a simple, room-plate-cavity model. Two materials with different elastic properties, aluminum and plywood, are selected for the elastic plate. The time domain results show a good agreement with the frequency domain approach beside a faster convergence to exact solution. Next, to show the method's basic application, the sound propagation in practical transmission problem is visualized in a room-plate-room model. The variation of sound pressure due to changes in plate thickness and plate material are discussed. This preliminary study shows the TDFEM basic applicability in solving a complicated vibro-acoustic problem.