Design Of Reliability Qualification Test Scheme Based On Weibull Distribution

Reliability refers to the ability of a product to complete a specified function within a specified time under specified conditions.With the continuous improvement of our country's industrialization level,whether it is military products or civilian products,the reliability requirements of products are constantly improving.The reliability level of a product is determined by multiple links including design,manufacturing,processing,and maintenance.Among them,one link that cannot be ignored is the reliability qualification test before the product is formally designed and finalized.At present,the reliability qualification test standard of our country's mechanical products generally adopts GJB899A-2009.This standard is formulated based on the exponential distribution of product life distribution.However,the life of mechanical products mostly obeys or approximately obeys the Weibull distribution.Therefore,this thesis studies this outstanding issue,mainly including the following:(1)The types,principles,design requirements,and basic parameters of the reliability qualification test are described in detail.The Weibull distribution model is introduced in detail,and the characteristics and main application scenarios of the Weibull distribution model are analyzed.(2)This thesis introduced the experimental principle of the time censoring test.For the timing censoring test with replacement,a multi-sample Weibull distribution renewal process calculation model was proposed,and the standard test scheme design and the limit quality scheme design were completed.For the timing censoring test without replacement,the mathematical equations for the design of the test scheme are given.Further combining with specific calculation examples,the scheme design in this thesis is compared and analyzed with the scheme in GJB 899A-2009 and a scheme design based on a non-homogeneous Poisson process,which proves the advantages of the scheme in this thesis.(3)This thesis carefully elaborated the principle of sequential probability ratio test in statistics and introduced the sequential test scheme derived from it.For two different failure product handling strategies with replacement and without replacement,sequential test schemes based on Weibull distribution were designed respectively.Combined with specific calculation examples,the sequential test scheme of this thesis is simulated and analyzed.(4)To solve the problem that how to determine the shape parameter m of the life distribution accurately,the parameter estimation method is used in this thesis to modify the shape parameters of the experimental Weibull distribution.However,the sample size of the qualification test is small and the estimation result is affected by the randomness of samples.So a small sample estimation method based on the S-SMART resampling method is proposed in this thesis.Further,combined with actual examples,the small sample estimation method based on the S-SMART resampling method is used to determine the shape parameters of the sample life distribution,and the scheme design is further completed,and the designed scheme is simulated and analyzed.