A general solution framework for time-variant reliability based design optimization

In this paper, a general solution framework called time-invariant equivalent method (TIEM) is proposed to solve the time-variant reliability based design optimization (RBDO) problems, which provides an efficient tool for reliability design of many complex structures or systems considering their whole life cycles. In each cycle, the proposed method constructs an equivalent time-invariant RBDO problem according to the time-variant reliability analysis results and then updates the design point by solving this problem. Therefore, the time-variant RBDO problem is decoupled into a series of time-variant reliability analyses and time-invariant RBDO problems that are alternately solved, which dramatically promotes the computational efficiency. Besides, an iteration mechanism is proposed to ensure the convergence of the whole optimization procedure. Finally, five numerical examples and an engineering application are investigated to demonstrate the effectiveness of the proposed method.