FATIGUE RELIABILITY EVALUATION OF STRUCTURE UNDER RANDOM LOADING USING SAFETY CRITERION PART II. APPLICATION

摘要

The concrete application of fatigue reliability evaluation methodology, proposed in Part I, to bodywork frame of urban transport vehicle is presented in this paper. On the base of information obtained on operational loading (#sigma#(t) process measured at required points of the frame) and material properties (Wohler's life-curve of the critical part of the frame determined for the most loaded point), the operational fatigue life of the frame designed was estimated and the fatigue-reliability with respect to the requirements put upon its operation was assessed by methodology presented in Part I.It is demonstrated in the work that to evaluate the service fatigue reliability of structure in view of fatigue-failure occurrence, the criterion of reliability evaluation using the safety in loading is indispensable. It is that nearly 40-multiple higher expected fatigue-life of the frame than required represents, or, is covered only by 1.8 multiple increase of mean value and standard deviation of the #sigma# (t) random loading process. The way of estimation of minimum value of safety needed to provide the reliable operation of the frame vehicle under expected load conditions is presented.