Indoor Sound Attenuation Based On The Finite Element Method

Distributing of sound field in reverberation room is an important part of room acoustics, but there are a lot of problems in this field, for example, sometimes the sound absorption coefficient is bigger than 1 when measuring it, but this does not accord with the define of sound absorption coefficient. This thesis discusses distributing and attenuation of sound field in reverberation room by the way of analytical and numerical (finite element) method to grounding for solving this problem.The way of analytical method is a way by which we can solve to simple room shape and border condition, basing on the theory of wave acoustics. The result of this method is theoretically right hi case of right solution, but it can solve only in simple case. This thesis solves to the equation of simple room shape and border condition by the powerful scientific numerical calculation software MATLAB, and draws relevant figures of Distributing of sound field in room to show distributing and attenuation of sound field hi reverberation room visually.Because the way of analytical method can solve only in simple case, the same with elastic mechanics, which is helpless to complex room shape (such as non- rectangle room) and border conditions(such as different sound absorption material walls), this thesis uses the way of finite element method as well to solve distributing and attenuation of sound field in reverberation room in complex case, so that it has significance of instruction for arranging sound absorption materials in practical situations, and it is compared with the result of analytical method to validate each other. In addition, in order to validate that method of finite element can solve to the complex border conditions, this thesis also gives an example of it.