Multiscalar DIC analyses of granular string under stretch reveal non-standard deformation mechanisms
Multiscalar DIC analyses of granular string under stretch reveal non-standard deformation mechanisms
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DOI：
10.1016/j.ijsolstr.2021.111402
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发表时间：
2022-01
影响因子：
3.6
通讯作者：
N. Nejadsadeghi;M. D. Angelo;A. Misra;F. Hild
中科院分区：
文献类型：
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作者：
N. Nejadsadeghi;M. D. Angelo;A. Misra;F. Hild
为测量经典行为而设计的机械测试不提供宏观响应背后的信息。多标量数字图像相关(DIC)可以用于这些实验，以揭示导致出现宏观尺度行为的微观机制。应用多标量DIC方法研究了具有手性的特殊颗粒线的拉伸行为。DIC是在宏观尺度上进行的，其中忽略了底层的微观结构，并将结构视为连续棒。此外，在微尺度的DIC分析中利用了潜在的微观结构，以揭示丰富的变形区域。此外，还进行了细观分析，以提取表征颗粒材料系统的刚体运动。这些分析是针对两种类型的表面图案进行的，测量不确定度被量化。微观结果表明，颗粒串可以看作是由一组接近刚性的颗粒组成的颗粒材料，这些颗粒通过晶间机制储存弹性能量。此外，结果还揭示了手性颗粒弦在拉伸过程中的非标准形变机制。这些机制包括连贯的颗粒旋转，而不是齿轮状的颗粒旋转。更值得注意的是，观察到了由颗粒互连行为控制的颗粒横向位移。
Mechanical tests designed to measure classical behavior do not provide information underlying the macroscale response. Multiscalar digital image correlation (DIC) can be employed in these experiments to expose the micromechanisms that lead to the emergent macroscale behavior. A multiscalar DIC methodology was applied to study the extensional behavior of a particular granular string with chiral properties. DIC was performed at the macroscale in which the underlying microstructure is overlooked and the construct is treated as a continuum bar. Further, the underlying microstructure was exploited in a microscale DIC analysis to expose the rich deformation regimes. In addition, a mesoscale analysis was carried out to extract the rigid body motions that characterize a granular material system. These analyses were performed for two types of surface patterns and measurement uncertainties were quantified. The microscale results show that the grain string can be treated as a granular material composed of a set of nearly rigid grains that store elastic energy through intergranular mechanisms. Further, the results reveal non-standard deformation mechanisms that underlie the chiral granular string subjected to extension. These mechanisms include grain rotations that are coherent as opposed to gear-like grain rotation. More notably, grain transverse displacements are observed that are controlled by the behavior of the grain interconnections.