Adam Valentin, Bergfeld Bastian, Weißgraeber Philipp, van Herwijnen Alec, Rosendahl Philipp L
Institute of Structural Mechanics and Design, Department of Civil and Environmental Engineering, Technical University of Darmstadt, Franziska-Braun-Str. 3, 64285, Darmstadt, Germany.
WSL Institute for Snow and Avalanche Research SLF, Flüelastr. 11, 7260, Davos, Switzerland.
Nat Commun. 2024 Sep 2;15(1):7379. doi: 10.1038/s41467-024-51491-7.
When porous materials are subjected to compressive loads, localized failure chains, commonly termed anticracks, can occur and cause large-scale structural failure. Similar to tensile and shear cracks, the resistance to anticrack growth is governed by fracture toughness. Yet, nothing is known about the mixed-mode fracture toughness for highly porous materials subjected to shear and compression. We present fracture mechanical field experiments tailored for weak layers in a natural snowpack. Using a mechanical model for interpretation, we calculate the fracture toughness for anticrack growth for the full range of mode interactions, from pure shear to pure collapse. The measurements show that fracture toughness values are significantly larger in shear than in collapse, and suggest a power-law interaction between the anticrack propagation modes. Our results offer insights into the fracture characteristics of anticracks in highly porous materials and provide important benchmarks for computational modeling.
当多孔材料承受压缩载荷时，可能会出现局部破坏链，通常称为抗裂纹，进而导致大规模结构失效。与拉伸裂纹和剪切裂纹类似，抗裂纹扩展的阻力由断裂韧性决定。然而，对于承受剪切和压缩的高孔隙率材料的混合模式断裂韧性，我们却一无所知。我们针对天然积雪层中的薄弱层开展了断裂力学现场实验。通过使用力学模型进行解释，我们计算了从纯剪切到纯坍塌的全范围模式相互作用下抗裂纹扩展的断裂韧性。测量结果表明，剪切时的断裂韧性值明显大于坍塌时的，并且表明抗裂纹扩展模式之间存在幂律相互作用。我们的研究结果为深入了解高孔隙率材料中抗裂纹的断裂特性提供了见解，并为计算建模提供了重要的基准。
