Dynamic patterns of compaction in brittle porous media
Dynamic patterns of compaction in brittle porous media
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DOI：
10.1038/nphys3424
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发表时间：
2015-10-01
期刊：
影响因子：
19.6
通讯作者：
Einav, Itai
中科院分区：
文献类型：
--
作者：
Guillard, Francois;Golshan, Pouya;Einav, Itai
脆性多孔介质在致密化过程中表现出各种不可逆模式，包括岩石（1-3）、泡沫（4）、谷物包（5）和雪（6）中的静止和移动压实带。我们最近在谷物包装中发现了移动的压实带（5）;在雪中也发现了类似的带（6）。然而，一般性的问题仍然存在：在什么条件下可以脆性多孔介质显示其他致密化模式？在这里，使用一个新的启发式晶格弹簧模型经历反复破碎事件，我们首先预测可能出现的新型的动态压实，然后我们发现并确认这些新的模式实验压缩谷物包。总之，我们区分三个观察到的压实模式：短暂的不稳定的压实带，多个振荡传播压实带让人想起相变附近的临界现象，扩散不可逆致密化。这三种不同模式的表现形式被映射在一个相图中，使用两个无量纲组，代表织物崩溃和外部耗散。
Brittle porous media exhibit a variety of irreversible patterns during densification, including stationary and moving compaction bands in rocks(1-3), foams(4), cereal packs(5) and snow(6). We have recently found moving compaction bands in cereal packs(5); similar bands have been detected in snow(6). However, the question of generality remains: under what conditions can brittle porous media disclose other densification patterns? Here, using a new heuristic lattice spring model undergoing repeated crushing events, we first predict the possible emergence of new types of dynamic compaction; we then discover and confirm these new patterns experimentally in compressed cereal packs. In total, we distinguish three observed compaction patterns: short-lived erratic compaction bands, multiple oscillatory propagating compaction bands reminiscent of critical phenomena near phase transitions, and diffused irreversible densification. The manifestation of these three different patterns is mapped in a phase diagram using two dimensionless groups that represent fabric collapse and external dissipation.