R-S-N Mathematical Model Based on TC18 by BW High Cycle Fatigue Test Data

Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》

朱良 王晶 李晓慧 锁红波 张亦良

Abstract： For the influence of stress ratio on fatigue life, fatigue tests of TC18 titanium alloy produced by build-up welding (TC18 by BW) samples were carried out under three stress ratios (R=0.5、R=0.06、R=-1), to draw three fatigue limits and 6 S-N curves of“stress amplitude life model ”and“ three-parameter model ”. Based on the integral relationship of the crack growth rate and fatigue life and considering both of mathematical models of fatigue life, a systematic investigation of the relationship between stress ratio (R) and fatigue life curve (S-N) was performed to build the fatigue life mathematical model (RS-N). According to the modified formula proposed in this paper, the establishment of two R-S-N mathematical models, applicable for TC18 by BW materials. The results show that“stress amplitude”model can accurately predict moderate fatigue life, and“three-parameter fatigue”model is more suitable for the prediction of long-life area. The predictive value of two proposed R-S-N mathematical models are in better agreement with the experimental values, they can accurately predict the fatigue curve under any stress ratio in engineering.

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