Accession Number : AD0889483

Title :   Failure Rates of Non-Homogeneous Parts Populations.

Descriptive Note : Technical operating rept.,

Corporate Author : AEROSPACE CORP EL SEGUNDO CA SYSTEMS ENGINEERING OPERATIONS

Personal Author(s) : Reed, A. C.

Report Date : 15 SEP 1971

Pagination or Media Count : 50

Abstract : Groups of similar manufactured devices tend to be non-homogeneous due to process variability. Quality control methodology is used to improve the quality of groups of manufactured devices, particularly with respect to reliability by rejecting anomalous devices. In this study, a mathematical model was developed in which the average failure rate observed in a manufactured lot of devices following screening is a function of the failure mechanisms remaining in the non-homogeneous population. Parametric studies of both operating and dormant part failure rates were performed using subgroups having different failure rate characteristics represented by Arrhenius, Eyring, and non-Arrhenius physical failure models. The effect of dormancy on failure rate was explored, and the results were consistent with a previously stated theory which states that the failure rates of high reliability parts remain almost as high when dormant as when operating. (Author)

Descriptors :   (*RELIABILITY, STATISTICAL ANALYSIS), (*QUALITY CONTROL, MATHEMATICAL MODELS), POPULATION(MATHEMATICS), FAILURE(MECHANICS), CURVE FITTING, GRAPHICS.

Subject Categories : Statistics and Probability
      Mfg & Industrial Eng & Control of Product Sys

Distribution Statement : APPROVED FOR PUBLIC RELEASE