Actual light deflections in regions of crack tips and their influence on measurements in photomechanics

Friedrich W. Hecker; Jerzy Pindera; Baicheng Wen

doi:10.1117/12.49496

1 December 1991 Actual light deflections in regions of crack tips and their influence on measurements in photomechanics

Friedrich W. Hecker, Jerzy Pindera, Baicheng Wen

Proceedings Volume 1554, Second International Conference on Photomechanics and Speckle Metrology; (1991) https://doi.org/10.1117/12.49496
Event: San Diego, '91, 1991, San Diego, CA, United States

Abstract

Crack-tip photomechanics are based on certain simplifying assumptions which are seldom discussed. In a recent paper of the authors theoretical bases of the shadow optical method of caustics have been analyzed and tested using results obtained by three analytical-experimental procedures, namely classical strain gages, isodynes and gradient-index method. It has been concluded that the gradient-index method appears to be a suitable tool for analysis of stress state near crack tips and notches and, in particular, for testing pertinent singular solutions of linear elastic fracture mechanics and ranges of their applicability. In the present paper, a more detailed analysis of all results obtained in light deflection experiments allows to quantify the contribution of both involved effects and to determine the distortion of the faces of the investigated plates along their crack planes. The ability of the strain-gradient method to analyze some features of the three-dimensional stress-state is reported. Finally, presented experimental evidence allows to draw conclusions related to limits of applicability of certain photomechanical measurements near crack tips.

Citation Download Citation

Friedrich W. Hecker, Jerzy Pindera, and Baicheng Wen "Actual light deflections in regions of crack tips and their influence on measurements in photomechanics", Proc. SPIE 1554, Second International Conference on Photomechanics and Speckle Metrology, (1 December 1991); https://doi.org/10.1117/12.49496

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