Abstract
This paper describes a noise reduction design of transient sound radiating from a thin plate structure excited by random impact forces. To reduce calculation costs in a structural modification, input power which is represented as product of probability density function and mode shape is presented. The input power of each mode is used as an objective function for an evaluation of sound reduction. In this structural modification, the shape of dimple adding on a thin plate is set as design variables and optimized. It is confirmed that the proposed input power is effective and useful for reduction of sound power.