Abstract: In practical engineering, parts with multiple weak sites are widely used; these sites can significantly decrease the reliability of the parts. Typical such parts are taken as research background, detailed theoretical analysis is carried out on aspects such as the load dependence of multiple weak sites in order to research the failure correlations among these sites. On this basis, minimum sequence statistics model is used to build the reliability model of isostructural multiple weak site parts, and the influences of strength decentrality and load decentrality on the reliability of multiple weak site parts are researched in depth. The results show that the failure law of a part with multiple weak sites is different from that of a part with only one weak site. Not only the safety margin has influence on the reliability of the part, the load roughness also has important influence on the part with multiple weak sites. The built model has guiding significance to the design and reliability assessment of parts with multiple weak sites.

Key words: Failure correlation, Multiple weak site, Reliability, Reliability modeling