Sequential optimisation and reliability assessment for multidisciplinary design optimisation under hybrid uncertainty of randomness and fuzziness

For engineering product design under uncertainty, it is important to guarantee the reliability and safety, especially for complex and coupled systems design problems, using multidisciplinary design optimisation (MDO). Due to the different cognitive levels to various uncertain parameters, it is necessary to include the mixed uncertain parameters such as the random parameters and fuzzy parameters into consideration simultaneously. The design problem under hybrid uncertainty of randomness and fuzziness presents a challenge. However, little attention has been paid to solve hybrid uncertainty problems until now. This study constructs the formulation of fuzzy random uncertainty-based MDO (FRMDO), and proposes a method to solve the FRMDO problems within the framework of sequential optimisation and reliability assessment (SORA), called the FRMDOSORA approach. The FRMDOSORA approach can be applied both in single-level and multi-level MDO methods, and can effectively solve MDO problems, where fuzzy, random and fuzzy-random uncertainties coexist. Case studies are given to demonstrate the efficiency and feasibility of the proposed FRMDOSORA approach.