Search Results

A hybrid method is developed by combining energy finite element method (EFEM) and energy boundary element method (EBEM) to predict interior noise of structural-acoustic systems at high frequencies. In the hybrid EFEM/EBEM method, the structural domain of the system is modeled by structural finite elements, and the acoustic domain is modeled by acoustic boundary elements. The structural vibration response is computed from EFEM. The interior sound pressure level in the acoustic domain is recovered using EBEM. To validate the hybrid method, the interior noise levels in simplified airplane cabin and van models are computed and compared with that of EFEM only model. Good correlations are observed.

Energy Finite Element Method (EFEM) is an alternative method to currently practiced Statistical Energy Analysis (SEA) for the solution of high frequency vibro-acoustic problems. In this paper, the theory of the energy finite element method for interior noise prediction is reviewed first. This is followed by the investigation of two example problems using EFEM; (a) the interior noise of an airplane cabin and (b) the sound transmission loss of a dash. In both case EFEM results are compared to SEA predictions. The EFEM and SEA results using different mesh density are also investigated. Further, the advantages of EFEM in the solution of high frequency vibroacoustic problems are discussed.

A new Energy Finite Element Formulation was developed for interior noise prediction that includes not only ‘the indirect transmission path associated but also the direct transmission path. The formulation was subsequently extended to model noise control treatments by incorporating appropriate modifications to structural-acoustic and acoustic-acoustic joint matrices. The formulations developed are implemented and the resulting computer program was validated by comparing the predictions from the present development to the results from alternative methods.