INTEGRATED COMPUTATIONAL DURABILITY ANALYSIS

A computer aided analysis method is described for durability assessmen t in the early design stages using multibody dynamic analysis, finite element stress analysis, and fatigue life prediction methods. From mul tibody dynamic analysis of a mechanical system, dynamic loads of a mec hanical component were calculated. Finite element stress analysis with substructuring techniques produced accurate stress fields for the com ponent. From the dynamic loads and the stress field of the component, a dynamic stress history at the critical location was produced using t he superposition principle. Using Neuber's rule, a local strain time h istory was produced from the dynamic stress history. The local strain based fatigue life prediction method was then used to predict ''crack initiation'' life of the critical component. The predicted fatigue cra ck initiation life was verified by experimental durability tests. This methodology can be combined with identification of weak links and opt imization techniques such that the design optimization for an entire m echanical system based upon durability is possible during the early pr oduct development stage.