Abstract
This paper describes a parameter-free free-form optimization method for vibrating shell structures to reduce radiated noise. Squared pressure is selected as objective function, and the pressure is calculated by solving fully coupled shell-acoustic interaction system. The optimum design problem is formulated as a distributed-parameter shape optimization problem under the assumptions that shell structures are varied in the out-of-plane direction to the surface and the thickness is constant. The shape gradient function and the optimality conditions derived using the material derivative method are applied to the free-form optimization method for shell. With this method, the smooth optimal free-form of a shell structure is obtained without any shape design parameterization, while minimizing the objective function. The validity of this method is verified through an example model.
