In this paper, a cumulative type of hazard function is proposed to study the fatigue reliability. The model concerns with two decay factors. One is so-called the imbedded decay factor which deals with the intrinsic weakness of mechanical element, the other is the process-dependent 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 extended to the case of stress varied problem. Once the stress is changed, the failure rate at the end of the preceding stage becomes the intrinsic weakness at the beginning of next stage. Thus the failure rate demonstrates cumulative characteristics. Meanwhile a in-stage loading adjustment for high-to-low situation is also discussed by achieving the fatigue resistance D-p as large as possible, where D-p is defined as [GRAPHICS] where S-i, nu, R(n) and n denote the loading stress, cyclic strain hardening exponent, fatigue reliability and number of cycles, respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.
