压剪应力场中组合裂纹扩展的动态光弹性研究

DYNAMIC PHOTOELASTIC ANALYSIS OF COMBINED CRACK PROPAGATION IN A COMPRESSION-SHEAR STRESS FIELD

摘要:

本文用动态光弹性方法对震源物理中几种典型组合裂纹的动态扩展过程进行了研究。首次成功地记录了这些组合裂纹在单轴压缩情况下动态扩展过程中的等差线条纹图,并得到了裂纹的扩展路径。根据实验结果,本文确认在远场压剪应力场中扩展张裂纹尖端的K_Ⅱd=0,并求出了K_Ⅰd,得出了在压剪应力场中该等裂纹属稳定扩展的结论。

Abstract:

In this paper, dynamic propagations of some typical combined cracks in the physics of earthquake focus are studied by means of dynamic photoelasticity. Dynamic isochromatic fringes of these crack propagations under uniaxial compression are first successfully recorded, and the crack paths are also obtained. Experimental results show that K_Ⅱd=0 at a running crack tip even in a compres-sion-shear stress field. Mode I dynamic stress intensity factors of running crack tips are deter-mined, and a conclusion of crack stable propagation in a compression-shear stress field is ob-tained.