Leveraging on a recently developed multiscale simulation method, we propose a pioneering strategy for the multiscale analysis of hydrogen-induced cracking in reactor pressure vessels that considers micro-voids, their influences on hydrogen diffusion as well as the operating pressure of the vessel. In the finite element analysis, the nodal lattice hydrogen concentration and displacements are exchanged bi-directionally between the macroscale and microscale within a monolithic solution procedure. During the analysis, the voids are shown to cause non-uniform lattice hydrogen diffusion and the trapping effect, resulting in inter-void hydrogen accumulation, is demonstrated. Based on the hydrogen concentration on the void surfaces, the void hydrogen pressure was calculated for the hydrogen-induced cracking analysis. It was found that both internal shearing and necking failure modes exhibited micro-structure dependence. The internal shearing mode caused oriented through-wall propagation of cracks in the vessel pressure while the internal necking mode promoted void nucleation in the reactor pressure vessel. As a result, during the early stages of void evolution, the oriented internal shearing of the dispersed small voids showed a high possibility to induce through-wall failure of the reactor pressure vessel.

中文翻译：

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反应堆压力容器氢致开裂的直接 FE2 多尺度建模


利用最近开发的多尺度模拟方法，我们提出了一种对反应堆压力容器氢致裂纹进行多尺度分析的开创性策略，该策略考虑了微空隙、它们对氢扩散的影响以及容器的工作压力。在有限元分析中，节点晶格氢浓度和位移在整体求解过程中在宏观尺度和微观尺度之间双向交换。在分析过程中，显示​​空隙会导致不均匀的晶格氢扩散，并证明了捕获效应，导致空隙间氢积累。根据空隙表面上的氢浓度，计算空隙氢压力以进行氢致裂纹分析。研究发现，内部剪切和颈缩失效模式均表现出微观结构依赖性。内部剪切模式引起容器压力中裂纹的定向穿壁扩展，而内部颈缩模式则促进反应堆压力容器中的空隙成核。因此，在空洞演化的早期阶段，分散的小空洞的定向内部剪切极有可能引起反应堆压力容器的穿壁失效。