孔隙岩石中的应力波传播和含止裂与闭合的动态断裂全响应
首发时间:2017-08-08
摘要:分离式霍普金森压杆冲击压缩单裂纹圆孔板砂岩试样,由于该试样独特的压缩致拉效应,冲击压缩载荷在圆孔边裂纹尖端产生拉伸应力波。借助粘贴在裂纹前方的应变片和裂纹扩展计,记录试样中应力波的传播,和裂纹动态起裂、快速扩展、止裂和再起裂扩展的全过程,以及裂纹动态起裂、扩展、止裂等特征时间参数。通过对比裂纹扩展计和应变片分别记录的特征参数出现的时间,得到裂纹扩展过程中运动裂纹突然止裂及裂纹面闭合的机理。裂纹尖端的拉伸应力波经试样自由界面反射成为压缩应力波,然后再次传播到运动裂纹尖端使得裂纹尖端突然止裂,并且使裂纹面闭合。
关键词: 动态断裂全过程; 裂纹闭合; 裂纹止裂; 应力波传播; 压缩单裂纹圆孔板
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STRESS WAVE PROPAGATION IN HOLED-CLEAVAGED ROCK AND COMPLETE DYNAMIC FRACTURE RESPONSE INCLUDING CRACK ARREST AND CLOSURE
Abstract:The SCDC (Single single cleavage drilled compression) specimens of sandstone were impacted by split Hopkinson pressure bar, because the sample's unique compression to pull, the tensile stress wave near the crack tip was generated by impact loading in sandstone specimen. Using strain gauge and CPG (Crack propagation gauge) glued ahead of crack to record the stress wave propagation in the SCDC specimen and the whole process of dynamical initiation, rapidly propagation, arrest and re-initiation. Besides, the strain gauge and CPG have the function to monitor the characteristic time parameter of dynamical crack initiation, propagation, arrest, reSTRESS WAVE PROPAGATION IN HOLED-CLEAVAGED ROCK AND COMPLETE DYNAMIC FRACTURE RESPONSE INCLUDING CRACK ARREST AND CLOSUREspectively. We preliminarily obtained the mechanism of the crack suddenly arrest and crack face closure by comparing the key time parameter tested by CPG and SG. The tensile stress wave generated from the crack tip propagated out and reflected by free sample face to become compression stress wave, which lead the running crack stop and a part of crack face closure.
Keywords: the whole process of dynamic fracture crack closure crack arrest stress wave propagation single cleavage drilled compression (SCDC)
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孔隙岩石中的应力波传播和含止裂与闭合的动态断裂全响应
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