Assessing the reliability of fast Fourier transform-based crystal plasticity simulations of a polycrystalline material near a crack tip
Assessing the reliability of fast Fourier transform-based crystal plasticity simulations of a polycrystalline material near a crack tip
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DOI：
10.1016/j.ijsolstr.2019.02.024
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发表时间：
2020-02-01
影响因子：
3.6
通讯作者：
Sangid, Michael D.
中科院分区：
文献类型：
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作者：
Rovinelli, Andrea;Proudhon, Henry;Sangid, Michael D.
晶体塑性模拟使得能够基于物理的描述与多晶材料中的微观结构属性相关联的微观力学场。与传统的有限元法（CP-FEM）相比，在周期性晶胞中实现晶体塑性的快速傅里叶变换（CP-FFT）提供了更高的计算效率。尽管如此，问题可能会出现有关的CP-FFT方法的准确性给出其基本的频谱框架，特别是在：潜在的文物，由于违反无牵引条件在内部自由表面内的单位细胞，吉布斯现象附近的区域急剧变化的局部机械性能，和表示的自由表面下的单位细胞的周期性的要求所施加的约束。本文提出了一种定制的大规模并行实现CP-FFT。对Ti 55531合金裂纹附近多晶变形的CP-FEM和CP-FFT模拟结果进行了直接比较。微观力学场和滑移系水平值被量化，并且在两种方法之间是相似的。在裂纹尖端的应力场的差异高达10%，该值消散后5体素（7 μ m）远离裂纹尖端。结果指向可靠地使用CP-FFT模拟来模拟多晶变形与基于所讨论的伪影的处理的警告。(C)2019爱思唯尔有限公司版权所有。
Crystal plasticity simulations enable a physically-based description of the micromechanical fields associated with microstructural attributes in polycrystalline materials. Fast Fourier transforms implementation of crystal plasticity (CP-FFT) in periodic unit cells offers increased computational efficiency compared to traditional finite element methods (CP-FEM). Albeit, questions may arise concerning the accuracy of the CP-FFT approach given its underlying spectral framework, specifically in regards to: potential artifacts due to violating the traction-free conditions at internal free surface within the unit cell, Gibbs phenomenon near regions with sharp changes in local mechanical properties, and representation of free surfaces under the constraints imposed by the requirement of periodicity of the unit cell. This paper presents a custom massively parallelized implementation of CP-FFT. A direct comparison of simulation results for polycrystalline deformation near a crack in a Ti55531 alloy is presented between CP-FEM and CP-FFT. The micromechanical fields and slip system level values are quantified and are similar between the two methods. Up to 10% difference in the stress fields is reported at the crack tip and this value dissipates moving away from the crack tip after 5 voxels (7 mu m). The results point towards the reliable use of CP-FFT simulations to model polycrystalline deformation with caveats based on the treatment of the discussed artifacts. (C) 2019 Elsevier Ltd. All rights reserved.