Acoustic radiation of an unbaffled vibrating plate with general elastic boundary conditions

If the simulations of the radiated field of a baffled plane structure has been deeply studied, the unbaffled case, although more realistic, has retained little attention. The proposed work investigates the radiation, in light fluid, of a plane unbaffled thin structure of finite dimensions and general elastic boundary conditions. The approach used is based on a variational formulation for the plate's displacement and the pressure jump through the structure. A Rayleigh-Ritz approximation with a polynomial set of trial functions is used for both variables. A good agreement is found with a numerical approach based on a boundary element method. Acoustic radiation of unbaffled rectangular plates will be discussed and compared to the baffled case. This will show in particular that the effect of the baffle is very important at low frequencies but there are no simple tendencies. Precise measurements confirm the validity of the simulations. (C) 1996 Acoustical Society of America.