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首页> 外文期刊>International journal of mechanics and materials in design >Discrete element simulation of dynamic behaviour of partially saturated sand
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Discrete element simulation of dynamic behaviour of partially saturated sand

机译:局部饱和砂土动力特性的离散元模拟

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The discrete element method (DEM) together with the finite element method (FEM) in LS-DYNA was employed to investigate the dynamic behaviour of sand under impact loading. In this approach, the partially saturated sand was modelled in DEM with capillary forces being taken into account through an implicit capillary contact model, while other solids were simulated using FEM. A slump test was first performed with dry sand to calibrate the contact parameters in DEM. Low velocity impact tests were then conducted to investigate the effect of water saturation on the shape and height of sand piles after impact, and to validate the simulations. It was found in the experiments that an increasing water saturation (in the range between 10 and 30 %) affected the height of sand pile for a given drop height due to an increasing cohesion between particles. The simulations captured the experimental ejecta patterns and sand pile height. Finally, a low confinement split Hopkinson pressure bar test from earlier literature was modelled; the DEM-FEM simulations could reproduce the trends of experimentally observed stress-strain curves of partially saturated sand under high strain rate loading, indicating that it was feasible to model dynamic behaviour of dry and wet sand with low saturation (< 20 %) in LS-DYNA; however, a number of questions remain open about the effect of grain shape, grain crushing and viscosity.
机译:采用离散元法(DEM)和有限元法(FEM)在LS-DYNA中研究了冲击载荷作用下砂土的动力特性。在这种方法中,部分饱和的沙子在DEM中建模,通过隐式毛细管接触模型考虑了毛细作用力,而其他固体则使用FEM进行了模拟。首先用干砂进行坍落度测试,以校准DEM中的接触参数。然后进行低速冲击试验,以研究含水饱和度对冲击后沙堆形状和高度的影响,并验证模拟结果。在实验中发现,由于颗粒之间的内聚力增加,对于给定的滴落高度,增加的水饱和度(在10%到30%之间)会影响沙堆的高度。模拟捕获了实验性的喷射模式和沙堆高度。最终,对早期文献中的低限制分裂霍普金森压力棒试验进行了建模。 DEM-FEM模拟可以重现在高应变速率载荷下部分饱和砂土的实验观察到的应力-应变曲线的趋势,这表明在LS中模拟低饱和度(<20%)的干湿砂岩的动态行为是可行的-DYNA;但是,关于晶粒形状,晶粒破碎和粘度的影响仍然存在许多问题。

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