Three-dimensional analysis of MMC microstructure and deformation by μCT and FE simulations
Three-dimensional analysis of MMC microstructure and deformation by μCT and FE simulations
复制标题
通过 μCT 和 FE 模拟对 MMC 微观结构和变形进行三维分析
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
F. Beckmann
中科院分区：
文献类型：
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作者：
H. Crostack;J. Nellesen;Gottfried Fischer;U. Weber;S. Schmauder;F. Beckmann
更好地了解颗粒增强金属基复合材料 (MMCp) 的微观结构在宏观失效之前在微观尺度上经历的微观变形和损伤过程，可以为这些材料的微观结构设计提供正确的方向。为此，我们进行了基于 μCT 的分析，结合了 μCT 实验和有限元模拟：由 MMCp 系统 Cobalt/Diamond 和 Al/B4C 组成的微小拉伸样品（横截面 A = 2 x 1 mm2）的标距长度通过断层扫描在不同变形阶段进行成像。 3D 应变张量场和位移矢量场由重建断层图像的数字图像相关性确定。根据未变形状态下分析体积的断层图，生成有限元网格，对接近现实的微观结构进行建模。使用这些网格和在体积边界测量的位移矢量场，对变形和损伤行为进行有限元模拟。实验发现两种复合材料的体积应变均低于 1%。变形场的空间分辨率受到特征微观结构长度的限制，特征微观结构长度取决于颗粒直径和颗粒间距。根据在分析的微观结构区域内采样的 3D 应变场对实验和模拟的结果进行比较。此外，还讨论了微观结构特征对应变局部化、局部损伤开始和复合材料连续失效的影响。
A better understanding of micro deformation and damage processes that the microstructure of particle reinforced metal matrix composites (MMCp) undergoes at microscale before macroscopical failure gives the right direction for the microstructural design of these materials. To this end, a μCT-based analysis was performed that combines μCT-experiments and FE simulations: The gauge length of tiny tensile specimens (cross-section A = 2 x 1 mm2) consisting of the MMCp systems Cobalt/Diamond and Al/B4C was imaged by tomography at different stages of deformation. 3D strain tensor fields and displacement vector fields were determined by digital image correlation of the reconstructed tomograms. Based on tomograms of the analyzed volume at the undeformed state, FE meshes were generated that model the microstructure close to reality. Using these meshes and the displacement vector fields measured at the volume boundaries, FE simulations of the deformation and damage behavior were carried out. In both composites volume strains below 1% have been found experimentally. The spatial resolution of deformation fields is limited by the characteristic microstructural length which depends on the particle diameter and the particle spacing. The results of the experiments and the simulations are compared on the basis of 3D-strain fields sampled within the analyzed microstructural region. Additionally, the impact of microstructural features on the localization of strain, the initiation of localized damage and the successive failure of the composite materials is discussed.