Hemmerle Arnaud, Yamaguchi Yuta, Makowski Marcin, Bäumchen Oliver, Goehring Lucas
Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany and Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex, France.
School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, UK.
Soft Matter. 2021 Jun 16;17(23):5806-5814. doi: 10.1039/d1sm00458a.
The mechanical properties of a disordered heterogeneous medium depend, in general, on a complex interplay between multiple length scales. Connecting local interactions to macroscopic observables, such as stiffness or fracture, is thus challenging in this type of material. Here, we study the properties of a cohesive granular material composed of glass beads held together by soft polymer bridges. We characterise the mechanical response of single bridges under traction and shear, using a setup based on the deflection of flexible micropipettes. These measurements, along with information from X-ray microtomograms of the granular packings, then inform large-scale discrete element model (DEM) simulations. Although simple, these simulations are constrained in every way by empirical measurement and accurately predict mechanical responses of the aggregates, including details on their compressive failure, and how the material's stiffness depends on the stiffness and geometry of its parts. By demonstrating how to accurately relate microscopic information to macroscopic properties, these results provide new perspectives for predicting the behaviour of complex disordered materials, such as porous rock, snow, or foam.
一般来说，无序非均匀介质的力学性能取决于多个长度尺度之间复杂的相互作用。因此，将局部相互作用与宏观观测结果（如刚度或断裂）联系起来，对于这类材料来说具有挑战性。在此，我们研究了一种由通过软聚合物桥连接在一起的玻璃珠组成的粘性颗粒材料的性能。我们使用基于柔性微量移液器偏转的装置，表征了单桥在拉伸和剪切下的力学响应。然后，这些测量结果以及来自颗粒填料X射线显微断层扫描的信息，为大规模离散元模型（DEM）模拟提供了依据。尽管这些模拟很简单，但它们在各个方面都受到经验测量的约束，并能准确预测聚集体的力学响应，包括其压缩破坏的细节，以及材料的刚度如何取决于其各部分的刚度和几何形状。通过展示如何准确地将微观信息与宏观性质联系起来，这些结果为预测复杂无序材料（如多孔岩石、雪或泡沫）的行为提供了新的视角。
