摘要
This study utilizes Direct FE^(2) multiscale simulation techniques to propose an innovative approach for analyzing hydrogen diffusion in Zircaloy cladding.This method combines finite element simulations at two scales into a monolithic framework by utilizing downscaling rules and scaling factors.Through the investigation,it was found that voids induce non-uniform diffusion of lattice hydrogen,demonstrating a strong correlation between trapped concentration and microstructure.Additionally,the accumulation of trapped hydrogen leads to localized plastic deformation and a reduction in effective diffusivity.Furthermore,two representative volume elements were established to depict the void distribution at various stages of its evolution.It is evident that in the initial phases of void evolution,the hydrogen-induced softening effect facilitates crack propagation deep within the zirconium alloy cladding.Moreover,as void evolution progresses into the second stage,this effect intensifies the incidence of localized damage at the narrow inter-void ligaments.
本文基于直接FE^(2)方法,提出多尺度模拟算法对锆合金包壳中的氢扩散行为进行了研究.该算法利用降尺度规则和缩放因子将两个尺度的有限元计算纳入单一计算框架.研究结果表明,微孔洞会引起氢沿晶格的非均匀扩散,而微孔洞分布将影响位错陷阱中的氢浓度.随着位错中氢浓度增加,局部塑性变形增加,氢在锆合金中的有效扩散率降低.此外,建立了两种代表性体积单元,分别体现孔洞演化过程不同阶段的分布特征.计算结果表明,在孔洞演化初期,氢致软化效应促进裂纹往锆合金包壳内部扩展.而在孔洞演化的第二阶段,氢致软化效应则会诱导产生孔洞间隙局部损伤.
基金
supported by the National Natural Science Foundation of China(Grant No.52301131)
Natural Science Foundation of Sichuan,China(Grant No.2023NSFSC0908)
Research Foundation for Talents of Chengdu Technological University(Grant No.2023RC017).
