Analysis of J-integral and HRR Singularity Using Experimental and Computational Hybrid Method with Image Processing

ABSTRACT This paper is concerned with the application of computer image processing technique to nonlinear fracture mechanics analyses. First, a new experimental and computational hybrid method to evaluate the J-integral is proposed. The displacement distribution near a crack tip is measured directly by means of the computer image processing technique. Then, the strain and the stress distributions are calculated, with which the J-integral is evaluated by the line integration technique. Since the method uses only the stress and strain values near the crack tip, the J-integral can be measured on arbitrarily shaped specimens. The second application of the computer image processing here is the experimental evaluation of the HRR (Hutchinson-Rice-Rosengren) singularity held from the displacement distribution near the crack-tip. To demonstrate the validity of these methods, a tensile test is performed on a compact specimen. Then, the J-integral values measured by the present method are compared with the Merkle-Corten equation. Also, comparing the experimental results with the numerical ones, the HRR singularity of the near-crack-tip is discussed in detail.

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