Experimental study on crushing characteristics and energy absorption effect of silica sand under dynamic loading
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摘要: 摘 要:为揭示动荷载下硅砂的破碎特性及吸能效应,基于改进的分离式霍普金森杆(SHPB)研究了四种粒组砂样的动力响应特征。结果表明,粒径和应变率会影响砂的动态应力-应变行为。砂的变形可分为弹性、屈服和塑性三个阶段,试样的压实过程主要由屈服阶段的塑性压密和塑性阶段的破碎压密组成;颗粒相对破碎指数与应变率及有效粒径均近似呈正比关系,而与分形维数呈反比;颗粒粒度对吸能效率的影响随颗粒特性的不同而变化(矿物组成、粒径及分化程度等);相同应力水平下,颗粒粒径越大,能量吸收效率越高;相同加载应变率条件下,颗粒越大,试样的峰值应力越小。为提高砂的吸能效率和减小负荷水平,建议采用较大粒径的硅砂。
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关键词:
Abstract: Abstract: This study investigates the dynamic response characteristics of silica sand under dynamic loading using the modified Split Hopkinson pressure bar (SHPB) to understand its crushing characteristics and energy-absorbing effects. Four different grain groups were examined, and the results demonstrate that the dynamic stress-strain behavior of the sand is influenced by grain size and strain rate. The deformation process of the sand can be categorized into three stages: elastic, yielding, and plastic. Plastic compaction dominates during the yielding stage, while crushing compaction is significant in the plastic stage. The relative crushing index of particles shows a direct relationship with both strain rate and effective particle size, while it is inversely related to the fractal dimension. The impact of particle size on energy absorption efficiency varies based on particle characteristics such as mineral composition, particle size, and degree of differentiation. At the same stress level, larger particle sizes exhibit higher energy absorption efficiency, and under the same loading strain rate conditions, larger particles experience lower peak stress. To enhance the energy absorption efficiency of sand and decrease the required loading level, it is advisable to utilize sand with larger particle sizes.
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