Pressure shock fronts formed by ultra-fast shear cracks in viscoelastic materials.
Pressure shock fronts formed by ultra-fast shear cracks in viscoelastic materials.
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DOI：
10.1038/s41467-018-07139-4
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发表时间：
2018-11-12
影响因子：
16.6
通讯作者：
Lapusta N
中科院分区：
文献类型：
--
作者：
Gori M;Rubino V;Rosakis AJ;Lapusta N
固体中自发传播的裂纹既发射压力波又发射剪切波。当剪切裂纹的传播速度比剪切波的速度的材料，由近裂纹尖端区域发射的剪切子波的合并形成一个冲击波阵面，显着集中粒子运动。对于压力波来说，这样的激波阵面是不可能的，因为在各向同性的线弹性固体中，裂纹不可能超过压力波的速度。在这项研究中，我们提出了全场实验测量的粘弹性聚合物中的动态剪切裂纹，导致形成的压力冲击前，除了剪切。经典理论的明显违反解释的聚合物的应变率相关的材料行为，其中裂纹速度保持低于最高的压力波速度普遍局部周围的裂纹尖端。这些发现对剪切裂缝（如地震）的物理和动力学有重要意义。固体中的剪切裂纹既发射剪切波又发射压力波，但通常认为只有当裂纹超过剪切波速度时，剪切波才聚结形成激波阵面。在这里，作者表明，局部材料硬化可以进一步增加破裂速度，并产生压力激波阵面，暗示在超音速传播。
Spontaneously propagating cracks in solids emit both pressure and shear waves. When a shear crack propagates faster than the shear wave speed of the material, the coalescence of the shear wavelets emitted by the near-crack-tip region forms a shock front that significantly concentrates particle motion. Such a shock front should not be possible for pressure waves, because cracks should not be able to exceed the pressure wave speed in isotropic linear-elastic solids. In this study, we present full-field experimental measurements of dynamic shear cracks in viscoelastic polymers that result in the formation of a pressure shock front, in addition to the shear one. The apparent violation of classic theories is explained by the strain-rate-dependent material behavior of polymers, where the crack speed remains below the highest pressure wave speed prevailing locally around the crack tip. These findings have important implications for the physics and dynamics of shear cracks such as earthquakes. Propagating shear cracks in solids emit both shear and pressure waves, but it is usually thought that only shear waves coalesce to form shock fronts when the crack exceeds the shear wave speed. Here, the authors show that local material stiffening can further increase rupture speed and produce pressure shock fronts that hint at supersonic propagation.
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影响因子：
56.9
作者：
Bouchon, M;Vallée, M
通讯作者：
Vallée, M
DOI：
10.1098/rspa.1990.0069
发表时间：
1990-06-08
影响因子：
--
作者：
FLECK, NA;STRONGE, WJ;LIU, JH
通讯作者：
LIU, JH
影响因子：
56.9
作者：
Decker, RB;Krimigis, SM;Lanzerotti, LJ
通讯作者：
Lanzerotti, LJ
影响因子：
8.6
作者：
Abraham, FF;Gao, HJ
通讯作者：
Gao, HJ
DOI：
10.1073/pnas.062012699
发表时间：
2002-04-30
影响因子：
11.1
作者：
Abraham, FF;Walkup, R;Seager, M
通讯作者：
Seager, M