材料の加工硬化特性を考慮した亀裂結合力モデルに基づく疲労亀裂の開閉口モデルと亀裂伝播解析

抄録

This paper presents a numerical simulation for fatigue crack propagation based on improved strip yield model, which enables the strain hardening effect of materials to consider. One-dimensional bar elements, which consist of the strain hardening materials, are plugged up the gap corresponding to the fictitious crack opening displacement in the plastic zone to describe the role of crack wake generated over fatigue crack surfaces. Validity of this numerical model under monotonic loading, unloading and reloading conditions was verified by comparison of the COD profile and plastic zones size with elastic-plastic FE analysis. Proposed model was implemented into the numerical simulation of fatigue crack propagation considering the crack opening / closing. Proposed simulation of fatigue crack propagation, which enables the strain hardening effect of materials, was validated by comparing fatigue crack propagation histories obtained by the numerical simulations with measured ones.