Pundir Mohit, Adda-Bedia Mokhtar, Kammer David S
Institute for Building Materials, <a href="https://ror.org/05a28rw58">ETH Zurich</a>, Switzerland.
Laboratoire de Physique, CNRS, <a href="https://ror.org/04zmssz18">ENS de Lyon</a>, Université de Lyon, 69342 Lyon, France.
Phys Rev Lett. 2024 May 31;132(22):226102. doi: 10.1103/PhysRevLett.132.226102.
Linear elastic fracture mechanics theory predicts that the speed of crack growth is limited by the Rayleigh wave speed. Although many experimental observations and numerical simulations have supported this prediction, some exceptions have raised questions about its validity. The underlying reasons for these discrepancies and the precise limiting speed of dynamic cracks remain unknown. Here, we demonstrate that tensile (mode I) cracks can exceed the Rayleigh wave speed and propagate at supershear speeds. We show that taking into account geometric nonlinearities, inherent in most materials, is sufficient to enable such propagation modes. These geometric nonlinearities modify the crack-tip singularity, resulting in different crack-tip opening displacements, cohesive zone behavior, and energy flows towards the crack tip.
线弹性断裂力学理论预测，裂纹扩展速度受瑞利波速度限制。尽管许多实验观察和数值模拟都支持这一预测，但一些例外情况对其有效性提出了质疑。这些差异的根本原因以及动态裂纹的确切极限速度仍然未知。在此，我们证明拉伸（I型）裂纹可以超过瑞利波速度并以超剪切速度扩展。我们表明，考虑到大多数材料中固有的几何非线性，足以实现这种扩展模式。这些几何非线性改变了裂纹尖端的奇异性，导致不同的裂纹尖端开口位移、内聚区行为以及流向裂纹尖端的能量流。
