A new model is presented to predict hydrogen-assisted fatigue. The model combines a phase field description of fracture and fatigue, stress-assisted hydrogen diffusion, and a toughness degradation formulation with cyclic and hydrogen contributions. Hydrogen-assisted fatigue crack growth predictions exhibit an excellent agreement with experiments over all the scenarios considered, spanning multiple load ratios, H2 pressures and loading frequencies. These are obtained without any calibration with hydrogen-assisted fatigue data, taking as input only mechanical and hydrogen transport material properties, the material's fatigue characteristics (from a single test in air), and the sensitivity of fracture toughness to hydrogen content. Furthermore, the model is used to determine: (i) what are suitable test loading frequencies to obtain conservative data, and (ii) the underestimation made when not pre-charging samples. The model can handle both laboratory specimens and large-scale engineering components, enabling the Virtual Testing paradigm in infrastructure exposed to hydrogen environments and cyclic loading.

翻译：本文提出了一种预测氢辅助疲劳的新模型。该模型融合了断裂与疲劳的相场描述、应力辅助氢扩散，以及包含循环与氢贡献的韧性退化公式。氢辅助疲劳裂纹扩展预测结果与所有考虑场景下的实验数据高度吻合，涵盖了多种载荷比、氢气压及加载频率。这些预测无需借助氢辅助疲劳数据进行校准，仅输入材料力学与氢传输特性、材料疲劳特征（基于单一空气环境测试）以及断裂韧性对氢含量的敏感性参数即可实现。此外，该模型还用于确定：(i) 获取保守数据所需的适宜测试加载频率，以及(ii) 未预先充氢样品时的性能低估程度。该模型既能处理实验室试样，也可应用于大型工程构件，为暴露于氢环境与循环载荷下的基础设施虚拟测试范式提供了支撑。