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基于CLoE与Gudehus-Bauer亚塑性模型数值模拟了平面应变条件下Hostun砂的应变局部化现象。从侧向压力和初始缺陷两个方面对比研究了两种模型所预测应变局部化的产生及演化模式。结果表明:(1)两种模型均能反映Hostun砂刚度随着侧向压力提高而增大的现象。(2)相比Gudehus-Bauer亚塑性模型,CLoE亚塑性模型所得出的应变局部化形态与试验结果更加一致。(3)CLoE亚塑性模型能够反映随着荷载增加,砂的体积先膨胀后缩小的特点。(4)相比Gudehus-Bauer亚塑性模型,CLoE亚塑性模型所得到的应变-应力曲线能够更明显地反映应变局部化带中单元的软化现象。(5)CLoE亚塑性模型能够更好地模拟由初始缺陷导致的不均匀应变。总的来说,所得的数值结果表明,CLoE亚塑性模型能够较好地模拟侧向压力和初始缺陷对应变局部化的影响,在模拟应变局部化现象方面较Gudehus-Bauer更有优势。然而,现有CLoE亚塑性模型无法考虑孔隙比,也未包含颗粒材料内尺度变量,有待进一步完善。
Strain localization of Hostun sand under plane strain was numerically simulated based on the CLoE and Gudehus-Bauer sub-plasticity models. From two aspects of lateral pressure and initial flaw, the generation and evolution modes of strain localization predicted by the two models are compared. The results show that: (1) Both models can reflect the increase of the stiffness of Hostun sand with the increase of lateral pressure. (2) Compared with the Gudehus-Bauer sub-plastic model, the strain localization of CLoE sub-plastic model is more consistent with the experimental results. (3) The CLoE sub-plasticity model can reflect the feature that the volume of sand expands and then shrinks as the load increases. (4) Compared with the Gudehus-Bauer sub-plastic model, the strain-stress curve obtained from the CLoE sub-plastic model can more clearly reflect the softening of elements in the strain localization zone. (5) The CLoE sub-plastic model can better simulate the non-uniform strain caused by the initial defect. In general, the numerical results obtained show that the CLoE sub-plastic model can better simulate the influence of lateral pressure and initial flaw on the strain localization and has more advantages than Gudehus-Bauer in modeling strain localization. However, the existing CLoE sub-plasticity model can not consider the void ratio, nor does it contain the internal variables of the granular material, and needs to be further improved.