ASSESSING THE SERVICE LIFE OF STRUCTURAL MATERIALS UNDER COMBINED PROCESSES OF LOW-CYCLE AND HIGH-CYCLE FATIGUE

A unified (combined) model of fatigue damage accumulation in structural materials in the ranges of low- and high-cycle fatigue under non-isothermal loading is presented. Under regular cyclic loading transition from low-cycle to high-cycle fatigue in the material is shown to go by degrees and depend on physical interaction of the mechanisms of high-cycle and low-cycle fatigue in the transition zone. The model is verified by comparing the computed fatigue curve for the 08X18H10T material with the experimental one. The results of the comparison show that the mathematical model developed adequately describes the combined effect of the low-cycle and high-cycle fatigue mechanisms. Key words: structural material, fatigue damage accumulation, low-cycle fatigue, high-cycle fatigue, mathematical model.