Life Prediction for Cable Insulation Material Based on Weibull Accelerated Testing Without Failures

Under strong assumptions associated with Weibull distributions for normal and accelerated test conditions, a statistical hypothesis-testing procedure is developed that permits the life of cable insulation material under normal stress conditions to be inferred from accelerated life-test data in which few, if any, breakdown owns occur. The procedure also yields an approximate relation between the number of tests required for testing under normal stress conditions and the number of tests required under accelerated test conditions. This relation, in turn, provides a graphical method for judging the feasibility of proposed accelerated life tests. Subject to the validity of the assumptions these procedures may have application to a broad range of materials, components, and systems.