Abstract Flexible obstacles are used to reduce the impact load exerted by granular flows. However, grain-scale interactions between granular assemblies and flexible obstacles remain poorly understood, making it difficult to estimate the required resisting force. In this fundamental study, a flexible obstacle was simplified as a grain intruder and dragged through a static granular assembly. A new physical intruder apparatus was used to calibrate a discrete element model. The calibrated model was then used to evaluate the effects of the stiffness and loading rate on the force experienced by the intruder and the energy dissipated by the granular assembly. The response of the intruder and the granular assembly depended significantly on both the drag rate and the obstacle stiffness. Softer obstacles caused longer sticks between slips. At least 60% of the work was transferred from the intruder into the granular assembly regardless of the drag rate and obstacle stiffness. Stick-slip behaviour was not observed for stiff obstacles and high drag rates (>1 m/s), where the bulk granular assembly fluidised. The results of this study suggest that rigid obstacles are better for causing energy dissipation in the granular assembly, while flexible obstacles are better for reducing the resisting forces required.

中文翻译：

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颗粒流与柔性障碍物之间的相互作用：颗粒尺度调查

摘要 柔性障碍物用于减少颗粒流施加的冲击载荷。然而，颗粒组件和柔性障碍物之间的颗粒尺度相互作用仍然知之甚少，因此难以估计所需的阻力。在这项基础研究中，一个灵活的障碍物被简化为一个颗粒入侵者，并被拖过一个静态颗粒组件。一种新的物理入侵者装置用于校准离散元件模型。然后使用校准模型来评估刚度和加载速率对入侵者所承受的力和颗粒组件耗散的能量的影响。入侵者和颗粒组件的响应在很大程度上取决于阻力率和障碍物刚度。较软的障碍物导致滑动之间的棍子更长。无论阻力率和障碍物刚度如何，至少有 60% 的工作从入侵者转移到颗粒组件中。对于坚硬的障碍物和高阻力速率 (>1 m/s)，没有观察到粘滑行为，其中散装颗粒组件流化。这项研究的结果表明，刚性障碍物更适合在颗粒组件中引起能量耗散，而柔性障碍物更适合减少所需的阻力。