Szabó Balázs, Török János, Somfai Ellák, Wegner Sandra, Stannarius Ralf, Böse Axel, Rose Georg, Angenstein Frank, Börzsönyi Tamás
Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary.
Institute of Physics, Budapest University of Technology and Economics, H-1111 Budapest, Hungary.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Sep;90(3):032205. doi: 10.1103/PhysRevE.90.032205. Epub 2014 Sep 10.
The evolution of wide shear zones or shear bands was investigated experimentally and numerically for quasistatic dry granular flows in split bottom shear cells. We compare the behavior of materials consisting of beads, irregular grains, such as sand, and elongated particles. Shearing an initially random sample, the zone width was found to significantly decrease in the first stage of the process. The characteristic shear strain associated with this decrease is about unity and it is systematically increasing with shape anisotropy, i.e., when the grain shape changes from spherical to irregular (e.g., sand) and becomes elongated (pegs). The strongly decreasing tendency of the zone width is followed by a slight increase which is more pronounced for rodlike particles than for grains with smaller shape anisotropy (beads or irregular particles). The evolution of the zone width is connected to shear-induced packing density change and for nonspherical particles it also involves grain reorientation effects. The final zone width is significantly smaller for irregular grains than for spherical beads.
针对剖分底部剪切盒中准静态干颗粒流，通过实验和数值方法研究了宽剪切带或剪切条带的演化过程。我们比较了由珠子、不规则颗粒（如沙子）和细长颗粒组成的材料的行为。对初始随机样本进行剪切时，发现该区域宽度在过程的第一阶段显著减小。与这种减小相关的特征剪切应变约为1，并且随着形状各向异性的增加而系统性增加，即当颗粒形状从球形变为不规则形状（如沙子）并变得细长（栓柱）时。区域宽度强烈减小的趋势之后是轻微增加，对于棒状颗粒而言，这种增加比对形状各向异性较小的颗粒（珠子或不规则颗粒）更为明显。区域宽度的演化与剪切诱导的堆积密度变化有关，对于非球形颗粒，它还涉及颗粒重新定向效应。不规则颗粒的最终区域宽度明显小于球形珠子的最终区域宽度。
