임의의 하중에 의해 발생하는 고주기 피로를 고려한 레벨셋 기반 위상최적설계

Abstract

This paper presents a design method for obtaining light weight structure without fatigue failure under random loading. Since the fatigue damage is sensitive to the boundary of structure, level set method is used to express the clear boundary. The rainflow cycle counting method, Goodman diagram, S-N curve, and Miner’s rule are employed to quantify the fatigue damage. The use of non-differentiable operators for calculating fatigue damage makes hard to analyze the design sensitivity of the fatigue constraint. To resolve this problem, these operators are approximated by using differentiable Heaviside function. The optimization problem is formulated to minimize the mass of the structure subject to the fatigue damage constraint. An example of cantilever beam is provided to verify the usefulness of the proposed method.