Wang Meng, Bouchbinder Eran, Fineberg Jay
The Racah Institute of Physics, <a href="https://ror.org/03qxff017">The Hebrew University of Jerusalem</a>, Jerusalem, 91904, Israel.
Chemical and Biological Physics Department, <a href="https://ror.org/0316ej306">Weizmann Institute of Science</a>, Rehovot 7610001, Israel.
Phys Rev Lett. 2024 Oct 11;133(15):156201. doi: 10.1103/PhysRevLett.133.156201.
Material failure is mediated by the propagation of cracks which, in realistic 3D materials, typically involves multiple coexisting fracture planes. Multiple fracture-plane interactions create poorly understood out-of-plane crack structures, such as step defects on tensile fracture surfaces. Steps form once a slowly moving, distorted crack front segments into disconnected overlapping fracture planes separated by a stabilizing distance h_{max}. Our experiments on numerous brittle hydrogels reveal that h_{max} varies linearly with both a nonlinear elastic length Γ(v)/μ and a dissipation length ξ. Here, Γ(v) is the measured crack velocity v-dependent fracture energy, and μ is the shear modulus. These intrinsic length scales point the way to a fundamental understanding of multiple-crack interactions in 3D that lead to the formation of stable out-of-plane fracture structures.
材料失效是由裂纹扩展介导的，在实际的三维材料中，裂纹扩展通常涉及多个共存的断裂面。多个断裂面相互作用会产生人们了解甚少的面外裂纹结构，例如拉伸断口表面上的台阶缺陷。一旦缓慢移动、扭曲的裂纹前沿分裂成由稳定距离h_max分隔的不连续重叠断裂面，台阶就会形成。我们对多种脆性水凝胶进行的实验表明，h_max与非线性弹性长度Γ(v)/μ和耗散长度ξ均呈线性变化。这里，Γ(v)是测量得到的与裂纹速度v相关的断裂能，μ是剪切模量。这些本征长度尺度为从根本上理解三维中导致稳定面外断裂结构形成的多裂纹相互作用指明了方向。
