Ritter Jonas, Löwe Henning, Gaume Johan
Institute of Materials Simulation (WW8) and Central Institute for Scientific Computing (ZISC), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland.
Sci Rep. 2020 Jul 24;10(1):12383. doi: 10.1038/s41598-020-67926-2.
Porous brittle solids have the ability to collapse and fail even under compressive stresses. In fracture mechanics, this singular behavior, often referred to as anticrack, demands for appropriate continuum models to predict the catastrophic failure. To identify universal controls of anticracks, we link the microstructure of a porous solid with its yield surface at the onset of plastic flow. We utilize an assembly method for porous structures, which allows to independently vary microstructural properties (density and coordination number) and perform discrete element simulations under mixed-mode (shear-compression) loading. In rescaled stress coordinates, the concurrent influence of the microstructural properties can be cast into a universal, ellipsoidal form of the yield surface that reveals an associative plastic flow rule, as a common feature of these materials. Our results constitute a constructive approach for continuum modeling of anticrack nucleation and propagation in highly porous brittle, engineering and geo-materials.
多孔脆性固体即使在压缩应力下也有坍塌和破坏的能力。在断裂力学中，这种奇异行为，通常称为反裂纹，需要合适的连续介质模型来预测灾难性破坏。为了确定反裂纹的通用控制因素，我们将多孔固体的微观结构与其在塑性流动开始时的屈服面联系起来。我们采用一种多孔结构的组装方法，该方法允许独立改变微观结构特性（密度和配位数），并在混合模式（剪切-压缩）载荷下进行离散元模拟。在重新标度的应力坐标中，微观结构特性的共同影响可以转化为屈服面的通用椭球形式，该形式揭示了一种关联塑性流动规则，这是这些材料的一个共同特征。我们的结果为高孔隙率脆性工程材料和地质材料中反裂纹成核和扩展的连续介质建模提供了一种建设性方法。
