Mai Thanh-Tam, Okuno Kenichiro, Tsunoda Katsuhiko, Urayama Kenji
Department of Macromolecular Science and Engineering, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan.
Research Department I, Central Research, Bridgestone Corporation, Tokyo 187-8531, Japan.
ACS Macro Lett. 2020 May 19;9(5):762-768. doi: 10.1021/acsmacrolett.0c00213. Epub 2020 May 8.
We characterize the crack-tip strain field in the high-speed (supershear) crack in the elastomers propagating faster than the shear wave speed of sound (). The dependence of steady-state crack velocity () on input tearing energy exhibits a crossover at ≈ between the subsonic ( < ) and supershear cracks ( > ). Several features of the crack-tip strain field such as strain-magnitude, extent boundary, and singularity exponent also change substantially accompanying the transition from subsonic to supershear cracks. The definite crossover of these characteristics at ≈ reflects the variations in the crack-growth mechanism: The inertia effect comes into play in the supershear crack. We also demonstrate that the azimuthal distribution of the local crack-tip strain has a close correlation with the macroscopic crack-tip shape, regardless of the regime of .
我们描述了弹性体中高速（超剪切）裂纹的裂纹尖端应变场，该裂纹的传播速度比剪切声速（）快。稳态裂纹速度（）对输入撕裂能的依赖性在≈处呈现出亚声速（<）裂纹和超剪切裂纹（>）之间的交叉。裂纹尖端应变场的几个特征，如应变幅度、范围边界和奇异性指数，也随着从亚声速裂纹到超剪切裂纹的转变而发生显著变化。这些特性在≈处的明确交叉反映了裂纹扩展机制的变化：惯性效应在超剪切裂纹中起作用。我们还证明，局部裂纹尖端应变的方位分布与宏观裂纹尖端形状密切相关，而与的状态无关。
