The Exploration of Superiority about the Non-probability Reliability-Based Design Optimization Compared to the Safety Factor Method

Abstract

Non-probability reliability-based design optimization (NRBDO) theory has been widely acknowledged as an advanced and advantageous methodology for complex structural system design, especially in practical engineering of aerospace. Conversely, the traditional safety factor (SF) design method faded out of the horizon of the designer since it considers only the mean value of design variable without the effect of dispersion properties, which has been verified to be not reasonable. In previous studies, only the physical interpretation that NRBDO method is superior compared to the SF method was given. In this paper, we make attempts to seek a mathematical explanation through design domain in which NRBDO method and SF method search for the optimal design solution, which presents strong evidences why NRBDO theory is more advanced and reasonable method from the aspects of mathematical proof. Eventually, the advancement of the NRBDO and the weakness of the SF method are illustrated with three numerical cases.