Unified reliability model for fuzziness and randomness of the basic variables and state variables in structure

Based on the randomness and fuzziness of the basicvariables and state variables, a unified reliability model is presented forthe fuzzy random structure. In the unified reliability model, a factor isintroduced to formulate the safe measure for the fuzzy random structure asthe same one for the random structure. After the membership function of thefuzzy variable is replaced by the equivalent probability density functionfrom the mathematical transition in the unified reliability model, theconventional reliability methods for random structure can be extended forthe fuzzy random structure directly. Due to the unchangeable possibilitydistribution of the fuzzy variable in the equivalent mathematic transition,the failure probability can be calculated precisely for the fuzzy randomstructure. And the unified reliability model for random fuzzy structure canbe extended to the structure with multiple variables from strength-stresstwo variables. Comparison in the illustrations shows that the presentedmethod is more suitable for engineering application than the existed methodsin the references.