Zeng Bin, Wei Xue-Fei, Tan Ji-Zuan, Zhang Ke-Shi
School of Civil Engineering and Transportation, Foshan University, Foshan 528225, China.
School of Mechatronic Engineering and Automation, Foshan University, Foshan 528225, China.
Materials (Basel). 2025 Aug 21;18(16):3920. doi: 10.3390/ma18163920.
Addressing the limitations of traditional fatigue life prediction methods, which rely on extensive experimental data and incur high costs, and given the current absence of studies that employ deformation inhomogeneity parameters to construct fatigue-indicator parameter (FIP) for predicting low-cycle fatigue (LCF) life of metals in hydrogen environments, this study firstly explores how hydrogen pre-charging influences the LCF behavior of hot-rolled ribbed bar grade 400 (HRB400) steel via experimental and crystal plasticity simulation, and focus on the relationship between the fatigue life and the evolution of microscale deformation inhomogeneity. The experimental results indicate that hydrogen charging causes alterations in cyclic hysteresis, an expansion of the elastic range of the stabilized hysteresis loop, and a significant reduction in LCF life. Secondly, a novel FIP was developed within the crystal plasticity finite element method (CPFEM) framework to predict the LCF life of HRB400 steel under hydrogen influence. This FIP incorporates three internal variables: hydrogen embrittlement index, axial strain variation coefficient, and macroscopic stress ratio. These variables collectively account for the hydrogen charging effects and stress peak impacts on the microscale deformation inhomogeneity. The LCF life of hydrogen-charged HRB400 steel can be predicted using this new FIP. We performed fatigue testing under only one loading condition to measure the corresponding fatigue life and determine the FIP critical value. This helped predict fatigue life under different cyclic loading conditions for the same hydrogen-charged material. We compared the experimental data to validate the novel FIP to accurately predict the LCF life of hydrogen-charged HRB400 steel. The error between the predicted results and the measured results is limited to a factor of two.
传统疲劳寿命预测方法存在局限性，依赖大量实验数据且成本高昂。鉴于目前尚无研究利用变形不均匀性参数构建疲劳指标参数（FIP）来预测金属在氢环境中的低周疲劳（LCF）寿命，本研究首先通过实验和晶体塑性模拟探索了氢预充对400级热轧带肋钢筋（HRB400）钢LCF行为的影响，并关注疲劳寿命与微观尺度变形不均匀性演变之间的关系。实验结果表明，充氢会导致循环滞后发生变化，稳定滞后环的弹性范围扩大，LCF寿命显著降低。其次，在晶体塑性有限元方法（CPFEM）框架内开发了一种新颖的FIP，用于预测氢影响下HRB400钢的LCF寿命。该FIP包含三个内部变量：氢脆指数、轴向应变变化系数和宏观应力比。这些变量共同考虑了充氢效应和应力峰值对微观尺度变形不均匀性的影响。使用这种新的FIP可以预测充氢HRB400钢的LCF寿命。我们仅在一种加载条件下进行疲劳测试，以测量相应的疲劳寿命并确定FIP临界值。这有助于预测同一充氢材料在不同循环加载条件下的疲劳寿命。我们比较了实验数据，以验证该新颖FIP能够准确预测充氢HRB400钢的LCF寿命。预测结果与测量结果之间的误差限制在两倍以内。
