Fuzzy time-dependent reliability modeling and analysis method for mechanisms based on strength degradation

Mechanism reliability includes structural reliability of mechanism components and kinematic reliability of the mechanism. In fact, in practice mechanism reliability usually considers only kinematic reliability of the mechanism. Strength degradation including fatigue, wear, corrosion, and motion error, etc., are major failure mechanism of systems, sub-systems or components. In this paper, it is based on mechanism synthesis. In addition, the paper considers time dependence of strength degradation and fuzziness of the state in mechanism reliability analysis. Strength degradation mainly includes motion error and wear. Fuzzy time-dependent mathematical model of reliability is established based on fuzzy time-dependent methods, such as PHI2MCS, and combined with traditional mechanical reliability analysis methods, such as FORMSORM. The paper considers fuzziness of the state at the same time. Thus, fuzzy time-dependent failure probability is able to compute. Two examples demonstrate the practicality and feasibility of the method.