The deformation of thin sheet aluminum and steel specimens subjected to mixed-mode I/III stable tearing experiments has been measured by using three-dimensional digital image correlation (3D-DIC). Features of crack growth in these mixed-mode I/III experiments are characterized, including (a) the specimen's deformed shape and 3D full-field surface displacement fields, (b) the load-crack extension curves and crack paths, (c) angular and radial distributions of polar strain components, and (d) COD variation as a function of crack extension. Results indicate that for the highly ductile aluminum and steel materials under remote mixed-mode I/III loadings ((PHI)(velence)30 deg, 60 deg) or remote Mode III loading ((PHI)(velence)90 deg) the deformations have almost identical angular and radial polar strain distributions, which are modified from those measured under nominal Mode I loading ((PHI)(velence)0 deg). Results confirm that introduction of a Mode III loading component lowers the value of the dominant strain component ahead of the growing crack tip while increasing the radial singularity of the strain as compared with mode I loading. The mixed mode I/III average stable COD for AL6061-T6 (GM6208 steel) is 4X (3X) greater than measured during Mode I stable tearing in the same material, with clear correlations between the variation of COD with loading angle and that of the crack tip strain component during crack growth.
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