Mechanical behaviour of micro-capsules and their rupture under compression
Mechanical behaviour of micro-capsules and their rupture under compression
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DOI：
10.1016/j.ces.2015.11.002
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发表时间：
2016-03-13
影响因子：
4.7
通讯作者：
Gekle, Stephan
中科院分区：
文献类型：
--
作者：
Ghaemi, Ali;Philipp, Alexandra;Gekle, Stephan
了解微胶囊（MC）的变形，特别是其破裂的机制是其在各种应用中的性能至关重要。机械不稳定性一方面可以是失效机制，导致不期望的释放，但另一方面可以用作释放触发器。在这项工作中，有限元分析与纳米压痕实验一起被施加到表征单填充的三聚氰胺-甲醛制成的MC的变形。模拟结果表明，胶囊经历不同的变形制度：从线性弹性变形开始，在进一步压缩的MC屈服和塑性变形。最后一步是应变硬化制度，其中最大应力迅速增加，直到MC破裂。最后，我们描述了从数值模拟和实验结果得到的MCs破裂机制。我们发现，轴向和径向应力导致显着变薄的外壳在MC的赤道，和周向应力导致破裂沿着子午线的MC。(C)2015爱思唯尔有限公司版权所有。
Understanding the deformation of micro-capsules (MCs) and especially the mechanism of their rupture is of crucial importance for their performance in various applications. Mechanical instability can on the one hand be a failure mechanism, resulting in undesired release, but can on the other hand be used as a release trigger. In this work, finite element analysis together with nano-indentation experiments is applied to characterize the deformation of single filled MCs made of melamin-formaldehyde. The simulations reveal that the capsules undergo different deformation regimes: starting from linear elastic deformation, upon further compression the MCs yield and are plastically deformed. The final step is a strain hardening regime, where the maximum stress rapidly increases till the MCs rupture. Finally, we describe the MCs rupture mechanism obtained from numerical simulation and experimental results. We show that the axial and radial stresses cause significant thinning of the shell at the MC's equator, and that the circumferential stress leads to rupture along the meridians of the MC. (C) 2015 Elsevier Ltd. All rights reserved.