LOADING ADJUSTMENT FOR FATIGUE PROBLEM-BASED ON RELIABILITY CONSIDERATIONS

In this paper, a cumulative type of hazard function is proposed to stu dy the fatigue reliability. The model concerns with two decay factors. One is so-called the imbedded decay factor which deals with the intri nsic weakness of mechanical element, the other is the process-dependen t decay factor which relates to the loading process. Experimental data are used to show that the proposed model is quite suitable to depict the dynamic reliability of fatigue problem. The analysis is also exten ded to the case of stress varied problem. Once the stress is changed, the failure rate at the end of the preceding stage becomes the intrins ic weakness at the beginning of next stage. Thus the failure rate demo nstrates cumulative characteristics. Meanwhile a in-stage loading adju stment for high-to-low situation is also discussed by achieving the fa tigue resistance D-p as large as possible, where D-p is defined as [GR APHICS] where S-i, nu, R(n) and n denote the loading stress, cyclic st rain hardening exponent, fatigue reliability and number of cycles, res pectively. (C) 1998 Elsevier Science Ltd. All rights reserved.