Finite element simulations of dynamic shear rupture experiments and dynamic path selection along kinked and branched faults
Finite element simulations of dynamic shear rupture experiments and dynamic path selection along kinked and branched faults
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DOI：
10.1029/2008jb006174
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发表时间：
2009-08
影响因子：
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通讯作者：
E. L. Templeton;A. Baudet;H. Bhat;R. Dmowska;J. Rice;A. Rosakis;C. Rousseau
中科院分区：
文献类型：
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作者：
E. L. Templeton;A. Baudet;H. Bhat;R. Dmowska;J. Rice;A. Rosakis;C. Rousseau
我们分析了剪切裂纹沿非平面、扭结和分支断层路径的形核和扩展，与最近Rousseau和Rosakis(2003,2009)在实验室断裂研究中使用的构型相对应。其目的是从数值上再现那些剪切断裂实验，并从中洞察当裂纹最初沿直线路径以II型方式扩展时，与断层中的弯曲或分支连接相互作用时的活跃过程。这些实验涉及Homalite-100(一种光弹性聚合物)薄板的冲击载荷，这些薄板沿着弯曲或分支的路径切割，并在除撞击地点附近的起动器缺口外的任何地方弱粘回。应变片记录和等差线的高速摄影提供了与冲击和断裂扩展相关的瞬时变形场的特征。我们发现，用简单的线性滑移弱化描述粘结界面的粘结强度和摩擦强度的动态显式二维平面应力有限元分析，可以再现大多数情况下通过弯曲和分支连接的定性断裂行为，并再现动态等值线图案照片所揭示的主要特征。扭结或分支的存在会导致破裂传播速度的突然变化。此外，有限元结果还允许比较沿主断层段和倾斜断层段累积的总滑移量。我们发现，沿倾斜断层的滑动比沿着主断层的滑动要小得多，其大小取决于分支角度和扭结或分支构型。
We analyze the nucleation and propagation of shear cracks along nonplanar, kinked, and branched fault paths corresponding to the configurations used in recent laboratory fracture studies by Rousseau and Rosakis (2003, 2009). The aim is to reproduce numerically those shear rupture experiments and from that provide an insight into processes which are active when a crack, initially propagating in mode II along a straight path, interacts with a bend in the fault or a branching junction. The experiments involved impact loading of thin Homalite-100 (a photoelastic polymer) plates, which had been cut along bent or branched paths and weakly glued back together everywhere except along a starter notch near the impact site. Strain gage recordings and high-speed photography of isochromatic lines provided characterization of the transient deformation fields associated with the impact and fracture propagation. We found that dynamic explicit 2-D plane-stress finite element analyses with a simple linear slip-weakening description of cohesive and frictional strength of the bonded interfaces can reproduce the qualitative rupture behavior past the bend and branch junctions in most cases and reproduce the principal features revealed by the photographs of dynamic isochromatic line patterns. The presence of a kink or branch can cause an abrupt change in rupture propagation velocity. Additionally, the finite element results allow comparison between total slip accumulated along the main and inclined fault segments. We found that slip along inclined faults can be substantially less than slip along the main fault, and the amount depends on the branch angle and kink or branch configuration.