RELIABILITY ASSURANCE METHOD OF PRODUCT MADE OF BRITTLE MATERIAL, MANUFACTURING METHOD, RELIABILITY ASSURANCE DEVICE, AND RELIABILITY ASSURANCE PROGRAM

摘要

PROBLEM TO BE SOLVED: To perform life prediction being a relationship between a load and a breaking probability after a predetermined period with a reduced frequency of tensile test, and guarantee the reliability, in a product made of a brittle material such as an optical fiber in which strength distribution comprises a mixed system of two Weibull distributions of a high strength area and a low strength area.SOLUTION: A reliability assurance method is characterized by including: a step of inputting data of the breaking strength showing tensile test results of multiple products; a step of finding non-reliability corresponding to multiple data and calculating a cumulative hazard value; a step of applying a set of the multiple data and the cumulative hazard value to a cumulative hazard function of a high strength area, and estimating a geometry parameter and a scale parameter to estimate the cumulative hazard function of the high strength area; and a step of calculating the relationship between a load and the breaking probability after a predetermined period based on the cumulative hazard function of the high strength area, and estimating a calculable range capable of predicting the breaking probability based on the input data of the breaking strength in the relationship.