The Research On Structural Reliability Universal Grey Number Method Based On Interval Uncertainty

Reliability analysis is the metric of structure function considering uncertain factors,which often have bad influence on engineering structures.Generally,reliability analysis research mainly contains probability method and non-probability method.The probability method has longer history,during which researchers got many big achievements.At present,the probability method has been applied into plenty of engineering fields.However,using probability method requires distribution character of random variables,otherwise,big mistakes would happen.Non-probability method,mainly referring to convex model method,can analyze reliability with less information,especially for interval model.If the variables are represented by interval,the upper and lower bound of the variables need to be acquired.This property is a big advantage in practical application and makes interval reliability analysis vary popular among researchers.But interval analysis has its own defects,such as interval extension.If the calculation is complex,interval extension will happen and make the result interval bigger than its true variation range,then the result will make no sense.To overcome interval extension,we introduce universal grey number,which can be transferred into interval and restrain interval extension.The main contents are presented as follows:1.Taking advantage of universal grey number,we transfer interval uncertain parameters into universal grey numbers,and propose a method of using universal grey number to predict fatigue lifetime interval.Two examples are used to verify its currency.2.Based on traditional fuzzy reliability analysis model,a new fuzzy reliability method is proposed.It describes the interval of uncertainty variables relating to basic parameter distribution by universal grey number.More accurate result interval can be acquired through universal grey operation.3.To deal with uncertain structures under multi-source uncertainties and transfer the hybrid analysis into interval reliability problem,a new method based on universal grey number interval analysis is proposed.It turns random variables into interval variables,which are described by universal grey number.Equal entropy principle and 3? theory are used for the transformation.Examples proves that the reliability result of this method is higher than interval operation and it overcome the interval extension.