Robust reliability optimization of mechanical components using non-probabilistic interval model

Mechanical components design is subjected to uncertainties in material and geometrical properties, loads and other variables. For reliability optimization design with uncertain parameters, based on the non-probabilistic reliability theory, robust design and optimal design method, the uncertain parameters of mechanical components are expressed by non-probabilistic interval variables, and a non-probabilistic measure and procedure for robust reliability computation is presented. Compared with the conventional probabilistic reliability optimization approach, the proposed method does not require a presumed probability distribution of the uncertain parameters and only the bounds or ranges of their variations are required. The optimal design for non-probabilistic robust reliability is formulated as a two level optimization problem, in which the first level minimizes the original robust optimal objective with the constraints of non-probabilistic reliability index, and the secondary level is used to identify the reliability index. The purpose of it is to get a tradeoff between the design objective and the robustness to uncertainties and satisfy the requirements for reliability. For instance, the robust reliability optimization of unidirectional wedge-typed overrunning clutch is proposed, and the results show that the proposed method is useful for mechanical components design and quality improvement.