Time-varying Reliability Analysis Of Aircraft Wing

Aircraft,as a carrier for people to rise to the high altitude,has realized people’s dream of flying to the sky from ancient times.The wing is the structure for aircraft to provide lift,and the safety and reliability of the wing structure is related to the safety and reliability of the whole aircraft.The traditional reliability of wing structure only considers the reliability in static mode,while ignoring the influence of time.This paper considers the influence of time on the basis of traditional reliability,which is more in line with the actual reliability of wing.Firstly,the stress situation of the aircraft during the take-off and landing cycle is analyzed,and the wing is modeled by using CATIA software.Under the action of cyclic load,the stress concentration position of the wing under cyclic load is obtained through finite element analysis,and the stress concentration situation of the contact surface at this position is obtained.Then,considering the variation of skin and stringer reliability with time,the theory of strength degradation and mathematical statistics are used to analyze the time-varying reliability under the action of strength variation and random load,and the time-varying reliability under three kinds of strength degradation forms are obtained.Finally,considering the correlation between the above two components,through the selection of parameters in the Copula function,the appropriate Copula function is found and used to establish the joint failure probability density between the skin and stringer of the wing structure with the strength obeying three degradation forms,and the reliability of the wing structure at different times is calculated.Compared with the joint failure probability obtained by Monte Carlo method,the relative error of the failure probability obtained by the two calculation methods is less than 1%.Therefore,the joint failure probability density function obtained by using Copula function is effective.In the case that the two components have correlation,the calculated reliability is higher,which is more in line with the actual situation.