The role of constitutive models in MPM simulations of granular column collapses
The role of constitutive models in MPM simulations of granular column collapses
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DOI：
10.1007/s11440-016-0436-x
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发表时间：
2016-02
期刊：
影响因子：
5.7
通讯作者：
E. Fern;K. Soga
中科院分区：
文献类型：
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作者：
E. Fern;K. Soga
颗粒柱坍塌是一个成熟的实验，它包括在平坦表面上有一个垂直的颗粒材料柱，并让它在重力作用下坍塌。尽管执行起来很简单，但柱倒塌的数值建模仍然具有挑战性。到目前为止，许多注意力都集中在评估各种数值方法在模拟大变形的能力，很少的触发机制和流动行为的本构模型的作用。此外，初始密度的影响及其相关的粘性和强度特性从未包括在分析中。过去的数值研究大多依赖于简单的本构关系，不考虑软化行为。本研究的目的是说明本构模型的影响，对故障的发生，流动行为和沉积轮廓使用的材料点法。采用三种本构模型模拟了两种不同几何形状和密度的颗粒柱的坍塌。模拟结果表明，本构模型的崩溃行为有双重影响。它定义了沿沿着平面扩散的可动质量的体积，并控制其能量的耗散。初始密度被发现，以提高故障角和流动行为，是更显着的小列比大的。通过对运动质量势能的分析，解释了两种崩塌机制的存在。
The granular column collapse is a well-established experiment which consists of having a vertical column of granular material on a flat surface and letting it collapse by gravity. Despite its simplicity in execution, the numerical modelling of a column collapse remains challenging. So far, much attention has been dedicated in assessing the ability of various numerical methods in modelling the large deformation and little to the role of the constitutive model on both the triggering mechanism and the flow behaviour. Furthermore, the influence of the initial density, and its associated dilatancy and strength characteristics, have never been included in the analyses. Most past numerical investigations had relied on simple constitutive relations which do not consider the softening behaviours. The aim of this study is to illustrate the influence of the constitutive model on the on-set of failure, the flow behaviour and the deposition profile using the material point method. Three constitutive models were used to simulate the collapse of two granular columns with different geometries and for two densities. The results of the simulations showed that the constitutive model had a twofold influence on the collapse behaviour. It defined the volume of the mobilised mass which spread along the flat surface and controlled the dissipation of its energy. The initial density was found to enhance the failure angle and flow behaviours and was more significant for small columns than for larger ones. The analysis of the potential energy of the mobilised mass explained the existence of two collapse regimes.