Evolution of mud-crack patterns during repeated drying cycles
Evolution of mud-crack patterns during repeated drying cycles
复制标题
DOI：
10.1039/b922206e
复制
发表时间：
2010-01-01
期刊：
影响因子：
3.4
通讯作者：
Routh, Alexander F.
中科院分区：
文献类型：
--
作者：
Goehring, Lucas;Conroy, Rebecca;Routh, Alexander F.
在泥浆中，经常可以看到近似直线或六边形瓷砖的裂纹图案。在这里，我们通过实验展示了干燥裂纹模式如何从 90 度接缝角度主导变为 120 度接缝角度。几毫米厚的膨润土层被反复润湿和干燥。干燥后，各层会破裂。当重新润湿时，这些裂纹明显闭合，但当该层重新干燥时，会形成类似的裂纹图案，裂纹沿着先前打开的裂纹的线条形成。延时摄影被用来展示在每一代干燥过程中各个裂缝打开的顺序是如何不同的。经过 25 次润湿和干燥后，观察裂纹图案的几何形状。发现裂纹之间的角度接近 120 度，弛豫时间约为 4 代。随着裂纹模式的演变，裂纹顶点的位置也随之逐渐变化。开发了一个简单的层中裂纹行为模型来解释这些观察结果，其中先前打开的裂纹的位置定义了薄弱线。
In mud, crack patterns are frequently seen with either an approximately rectilinear or hexagonal tiling. Here we show, experimentally, how a desiccation crack pattern changes from being dominated by 90 degrees joint angles, to 120 degrees joint angles. Layers of bentonite clay, a few mm thick, were repeatedly wetted and dried. When dried, the layers crack. These cracks visibly close when rewetted, but a similar crack pattern forms when the layer is redried, with cracks forming along the lines of previously open cracks. Time-lapse photography was used to show how the sequence in which individual cracks open is different in each generation of drying. The geometry of the crack pattern was observed after each of 25 generations of wetting and drying. The angles between cracks were found to approach 120 degrees, with a relaxation time of approximately 4 generations. This was accompanied by a gradual change in the position of the crack vertices, as the crack pattern evolved. A simple model of crack behavior in a layer where the positions of previously open cracks define lines of weakness is developed to explain these observations.