Osmotic instability in soft materials under well-controlled triaxial stress
Osmotic instability in soft materials under well-controlled triaxial stress
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DOI：
10.1016/j.jmps.2022.105195
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发表时间：
2022-12
影响因子：
5.3
通讯作者：
Zhengjing Wang;Junjie Liu;Peijian Chen;Z. Suo
中科院分区：
文献类型：
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作者：
Zhengjing Wang;Junjie Liu;Peijian Chen;Z. Suo
生物组织和一些工程材料含有水分。当湿材料失去水分时，高三轴拉伸应力可能会积聚并导致不稳定。三轴拉伸失稳机理的研究引起了人们的极大关注，但定量研究仍是一个挑战。在此，我们发展了一种实验方法，施加控制良好的三轴拉应力，并观察渗透不稳定性在现场。我们在弹性体管中合成水凝胶，它们之间具有很强的粘附力。弹性体溶解微量的水，但允许水扩散出来，并将水凝胶置于均匀的等三轴拉伸应力下。我们开发了一种方法来确定应力作为时间的函数。透明的设置可以观察各种类型的渗透不稳定性，包括空腔成核，裂纹扩展和表面起伏。值得注意的是，我们的方法能够测量从10 - 5 m/s到与瑞利波速度10 - 1 m/s相当的极限的裂纹速度。我们观察到一个大的跳跃在临界能量释放率的裂纹速度。这项工作为研究高三轴拉伸下软材料的物理性质提供了机会。
Living tissues and some engineering materials contain water. When a wet material loses water, high triaxial tensile stress may build up and cause instability. The mechanism of instability under triaxial tension has attracted great attention, but quantitative study remains an ongoing challenge. Here we develop an experimental method to apply well-controlled triaxial tensile stress and observe osmotic instabilityin situ. We synthesize a hydrogel in an elastomer tube with strong adhesion between them. The elastomer dissolves minute amount of water, but allows water to diffuse out and places the hydrogel under homogeneous, equal-triaxial, tensile stress. We develop a method to determine the stress as a function of time. The transparent setup enables observation of various types of osmotic instabilities, including cavity nucleation, crack propagation, and surface undulation. Notably, our method enables the measurement of crack speed from ∼10−5m/s to a limit comparable to the Rayleigh wave speed ∼1 m/s. We observe a large jump in crack speed at a critical energy release rate. This work opens opportunities to study the physics of soft materials under high triaxial tension.