Fuzzy Fatigue Reliability Analysis for a Landing Gear Structure

Abstract

According to the conventional structure reliability theory, the bigger stress than the fatigue limit will bring some damage which can be accumulated. When the stress is smaller than the fatigue limit, there will be no damage to the structure. The model uncertainty can not be disposed very well by the conventional fatigue reliability theory. Fuzzy math theory can be used to describe the model uncertainty. So, the fuzziness of structural fatigue problem is described in this paper and calculated by the fuzzy math theory. The "cumulative damage - critical damage" dynamic interference model based on the Miner linear cumulative fatigue damage theory is established. Taking a nose landing gear as an example, the fatigue damage is predicted first through the fatigue analysis. The varying reliability along with the fatigue life of the landing gear can be obtained by the fuzzy math theory. The results show that the fuzzy fatigue reliability analysis has much more practicality and flexibility.