Research on the Relationship between Component Screening Level and Helicopter Application Level
By studying the standards of NASA,the screening standards of Aerospace Science and Technology Group and the national military standards for screening military electronic components,the differences in the definitions of different application levels are found.By analyzing the actual use of helicopters,it can be concluded from the analysis of mission time that there is no airborne electronic equipment of aerospace application level 1 on helicopters.The screening of components can not improve the inherent reliability of individual components,but only improve the use reliability of batch components by eliminating early failures.However,it is not the case that the stricter the screening conditions is,the higher the use reliability of batch components will be.Taking the high-temperature burn-in of integrated chips in component screening as an example,the residual life assessment after aerospace level 1 screening and level 2 screening is calculated respectively.The critical value of the life test is calculated by the screening formula provided in GJB/Z 34 and the allowable rejection rate(PDA)recommended in GJB 7243.The steady-state life test time of the integrated chip in GJB 548B is less than the critical value of the minimum life test,that is,the expected remaining life of the integrated chip after the aerospace application level 1 is less than that of the aerospace application level 2.The vast majority of helicopter airborne electronic products are of application level 2 or 3.
NETL
NSTL
万方数据
维普
