Abstract
A newly devised video-optical experimental technique allows for the automated determination of the in-plane, plane-stress components of the infinitesimal deformation tensor at discrete locations over an area of interest in a loaded specimen. It was used to evaluate a square area enclosing the central crack in a 5052-H32 aluminum panel loaded in tension. These experimental strain-tensor values were then used to evaluate theJ integral assuming that the mechanical behavior of the plate material is approximated by deformation plasticity theory.
TheJ integral was evaluated using two series of rectangular paths. The first was symmetrical about a horizontal axis passing through the notch length, using strain-tensor values at points to the left and right of a vertical axis passing through the center of the notch, with varying breadth and height. The second series were asymmetrical about either axis, with varying breadth and height. The latter paths served to evaluate the experimental error associated with each of the four quadrants of the plate. TheJ integral is found to be path independent within the range of experimental error associated with the video-optical experimental-measurement technique. An independent verification of theJ integral value is obtained using a calculation related to the crack-mouth-opening displacement (CMOD). It is found to agree well with the values obtained by this new procedure.
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Cardenas-Garcia, J.F., Read, D.T. & Moulder, J.C. Experimental study of path independence of theJ integral in an aluminum tensile panel. Experimental Mechanics 27, 328–332 (1987). https://doi.org/10.1007/BF02318099
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DOI: https://doi.org/10.1007/BF02318099