New Analytical Method for Modeling Active Structure Acoustic Control System within an Irregular Enclosure

Abstract

A new analytical method for the acoustic-structure coupled problem within an irregular enclosure, which has both inner sound sources, and exterior forces exciting it, was developed based on a method called the covering domain method. The method is not only more accurate and faster than numerical methods, such as FEM/BEM, but also can be used to solve acoustic-structure coupled problems within any irregular enclosure in a convenient way, that are impossible for the traditional analytical method. The model for, the active structure acoustic control (ASAC) system of an irregular enclosure based on the method above was founded, and then the optimized actuators outputs were given, which is the key step for ASAC system design. Then the method was applied to a car-like-cavity and it was found that the simulation result is quite good and shows us this new general analytical method for solving active structure acoustic control problems within an irregular enclosure considering acoustic-structure coupling to be quite effective and fit for any irregular enclosure.Key words: acoustic-structure coupling; ASAC; irregular enclosure, analytical method INTRODUCTIONThe noise problem of passenger cabins in vehicles is becoming more and more acute with increasing demand for better performance and user satisfaction. Up to now a significant amount of research has been performed to develop active control technologies for quieting low-frequency noise in the cabins of vehicles and aircraft. 1,2 The previous investigations show that the low-frequency interior noise in closed cabins is mainly caused by structural-acoustic coupling. 3 The complicated structuralacoustic coupling behaviour of cabins, however, makes it quite difficult to implement an ASAC (Active Structure Acoustic Control) system that controls sound radiated by all the vibrating boundaries. Consequently, the key to implementing practical ASAC system depends heavily on the full analysis of structural-acoustic coupled systems.The problem has drawn the interest of many researchers during recent decades. Currently, typical ways to solve the acoustic-structure coupling problem are the energy method, the numerical method and the analytical method.The energy method, such as SEA or EFM 4 , is not fit for the low-frequency case and cannot provide the distribution of the sound level in the enclosure.The numerical methods, represented by FEA/BEM and SUP, are not only timeconsuming but also lack the full details of the coupling system that are important for control. Furthermore, it is costly to build a CAD model for complex cavities, which

Active structural acoustic control of transmitted sound through a double panel partition by weighted sum of spatial gradients

“…The other one is the active structural acoustic control (ASAC) technique in which the sound radiated by structures is controlled using one or several control actuators applied directly on the vibrating structures. 10–13 The benefits of ASAC over ANC are associated with the control of sound at the source and the system compactness. Structurally applied actuators are much less intrusive than speakers because they do not use space in the acoustic field.…”

The patch effect on the vibro-acoustic coupling of an irregular enclosure backed with a PZT-bonded panel

“…. , N, (12) where L lmn,i j is the coupling coefficient between the lmnth acoustic mode ψ lmn (α) and the i jth structural mode ϕ i j , and…”

“…For regular enclosures, e.g., rectangular or cylindrical ones, the structural vibration radiates sound into an enclosure through its coupling with acoustic modes in a very selective way [1][2][3][4][5][6]. However, for irregular enclosures, e.g., automobile cabins or aircraft fuselage shells, a slight imperfection in geometry affects the acoustic mode shapes [7][8][9] and, in turn, alters the coupling nature as well as the sound radiation [10][11][12][13][14]. Among topics related to vibro-acoustic analysis, an interesting one comes from the extensive implementation of active noise control schemes, which attenuate the interior noise of an enclosure by suppressing the structural vibration through PZT actuators bonded to the plate [15][16][17][18][19][20].…”

Sound–Structure Coupling Analysis of Multi-Flexible Plates Enclosure

“…How to coordinate the whole and part control become a concern research field [1,2] .Li research the relationship between the transmission path and the control strategies [3] . Zhang constructed an irregular enclosure to research new analytical method for the acoustic-structure coupled problem, his result show the method for solving Active Structure Acoustic Control problems to be quite effective [4] . Gu developed a model of structural-acoustic coupled system of a rectangular enclosure involving two simply supported flexible plates, using this model the acoustical potential energy and the optimal secondary control forces are derived theoretically [5] .…”