A mechanism-based multi-trap phase field model for hydrogen assisted fracture
A mechanism-based multi-trap phase field model for hydrogen assisted fracture
复制标题
DOI：
10.1016/j.ijplas.2021.103044
复制
发表时间：
2021-06-01
影响因子：
9.8
通讯作者：
Martinez-Paneda, Emilio
中科院分区：
文献类型：
--
作者：
Isfandbod, Mehrdad;Martinez-Paneda, Emilio
我们提出了一种新的基于相场的机理公式来预测氢脆。开发的多物理模型首次结合了基于泰勒的位错模型来解决裂纹尖端变形的力学问题。这使得能够捕捉到位错硬化机制在提高裂纹尖端前几十微米范围内的拉应力、氢浓度和位错陷阱密度方面的作用。将本构应变梯度塑性模型耦合到相场方程，模拟断裂过程，并耦合到多陷阱氢输运模型。对静态裂纹和扩展裂纹的分析表明，所提出的模型框架能够很好地捕捉到氢浓度、加载速率、材料强度和塑性长度尺度的敏感性。此外，将模型预测与高强度钢缺口拉伸强度与氢含量关系的实验数据进行了比较，得到了很好的一致。我们定义和实施了基于原子论和唯象的氢分解定律，并讨论了相似之处、不同之处和对无参数氢脆模型发展的启示。
We present a new mechanistic, phase field-based formulation for predicting hydrogen embrittlement. The multi-physics model developed incorporates, for the first time, a Taylor-based dislocation model to resolve the mechanics of crack tip deformation. This enables capturing the role of dislocation hardening mechanisms in elevating the tensile stress, hydrogen concentration and dislocation trap density within tens of microns ahead of the crack tip. The constitutive strain gradient plasticity model employed is coupled to a phase field formulation, to simulate the fracture process, and to a multi-trap hydrogen transport model. The analysis of stationary and propagating cracks reveals that the modelling framework presented is capable of adequately capturing the sensitivity to the hydrogen concentration, the loading rate, the material strength and the plastic length scale. In addition, model predictions are compared to experimental data of notch tensile strength versus hydrogen content on a high-strength steel; a very good agreement is attained. We define and implement both atomistic-based and phenomenological hydrogen degradation laws and discuss similarities, differences and implications for the development of parameter-free hydrogen embrittlement models.