Full Field Measurements of the Dynamic Deformation Field Around a Growing Adiabatic Shear Band at the Tip of a Dynamically Loaded Crack or Notch
CALIFORNIA INST OF TECH PASADENA
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The method of Coherent Gradient Sensing CGS is used to record the deformation field around an adiabatic shear band emanating from a pre-crack tip in C-300 steel loaded dynamically in mode-II. At early times after impact, the resulting fringe pattern surrounding the shear band seems to exhibit the deformation characteristics of a mode-II Dugdale plastic zone evolving under small scale yielding conditions, and, as a result, the experimental fringe patterns are fitted to the theoretical Dugdale crack deformation field by using a least squares fitting scheme. This results in values for the shear band length and the average shear stress acting on the shear band as functions of time. The average shear stress in the shear band decreases from 1.6 GPa at initiation to 1.3 GPa during the later stages of propagation.
- Metallurgy and Metallography