Application Of Wave Based Method-Statistical Energy Analysis For Mid-Frequency Coupled Structure-acoustic System

As a typical closed acoustic-structure cavity system in middle frequency range,automobile not only has subsystems with low modal density which are represented as a deterministic system,such as beams,A and B pillar,but also do has subsystems with high modal density which are represented as a statistical system,such as windshield and hood.The simple Finite Element Method(FEM)and Statistical Energy Analysis(SEA)cannot be used in the simulation analysis of this frequency range.So,the acoustic-structure coupling in middle frequency range is still a difficult problem.In this paper,hybrid WBM-SEA(Wave Based Method-Statistical Energy Analysis)is discussed to the problem of middle frequency acoustic-structure coupling problem.Firstly,from the respect of wave approach,the subsystem with low modal density is described by WBM,while the subsystem with high modal density is described by SEA.The two methods are linked together by “diffuse field reciprocity relation” and the application of the hybrid method in coupling system is derived.The acousticstructure,acoustic-structure-acoustic and structure-acoustic-structure coupling systems were established and the results of SEA plate velocity and sound pressure of a base point is calculated,which demonstrates the effectiveness of WBM-SEA model.The velocity convergence curve is obtained to verify the efficiency of WBM-SEA compared with FEM-SEA.Secondly,Aiming at the general defect of the geometric applicability of wave function method,the simple non-convex domain model is decomposed into convex subdomains to realize the application of WBM-SEA in non-convex models.An L-shaped acoustic-structure coupling system was established.The results of the reference sound pressure,SEA plate energy and a plane sound pressure cloud image were calculated to demonstrate the correction of WBM-SEA model.In order to further improve the application range of WBM-SEA,FEM are combined to derive the method of applying FEM-WBM-SEA to acoustic-structure coupling model.The validity and high convergence of FEM-WBM-SEA are verified by taking a car model as an example,which provides reference for improving the geometric applicability of WBM-SEA.Finally,in order to verify the correctness of the WBM-SEA method used in this paper,and experimental model equivalent to the simulation model was established.By comparing the acceleration of the SEA plate,the simulation result was compared with the experimental results to demonstrate the correctness of WBM-SEA in acoustic-structure coupling system.