Robust design to minimize eigen frequency variance of structure by stochastic finite element method

Abstract

Recently, in a mechanical structure development focusing on noise and vibration, a numerical analysis like finite element method is the most famous method to expect and improve noise and vibration characteristics of the structure. However, the method is not taken account of uncertainties in structure like part shapes and connecting parts in many cases. It leads to differences between actual these characteristics and results from numerical analysis. And, the quality of the product is probably deteriorated by the uncertainties. Therefore, it is important to suppress the variation of the noise and vibration characteristics by the uncertainties, which is called robust design. In this paper, it is discussed about robust design method to minimize the variation of the eigen frequency by the uncertainties. The robust design method is based on stochastic finite element method and structural optimization. To evaluate the ability of the method, the robust design method is applied to an FE model and a spring mass system, and the method is also tested by the actual structure to confirm the performance.

Keywords

• robustness
• uncertainty
• finite element method
• optimum design
• eigen frequency