Mixed Mode Stress Intensity Factors for a Slanted Crack Interacting With a Horizontal Crack in a Large Plate Under Remote Tension

Extensive studies have been carried out on the mutual influence of adjacent parallel cracks. However, to date, no solutions are available for non-parallel cracks proposed for FFS applications. The present analysis addresses this problem by evaluating the mixed mode fracture behavior of a slanted crack of length 2a2 influenced by an adjacent nonaligned horizontal crack of length 2a1. The cracks are placed in the center of a large plate under remote tension. A comprehensive parametric study was undertaken of the Stress Intensity Factors (SIFs) at the tip of the slanted crack adjacent to the horizontal crack. The parameters that affect the magnitudes of SIFs at the aforementioned crack tip include the slant angle (β), the horizontal separation (S), the vertical gap (H) between the two cracks, and the crack length ratio a2/a1. Both mode I and mode II SIFs, the mixed mode fracture parameters, are evaluated for a wide range of the slant angles β = 0°∼75° of the slanted crack, the normalized crack gaps of H/a2 = 0.4∼2, and normalized crack separation distances S/a2 = −0.5∼2. The cracks are modeled numerically using the ANSYS MECHANICAL APDL finite element program. It is found that both Mode I and Mode II SIFs manifest certain distinct behaviors that are different from those of an isolated single slant crack or from those of two parallel non-aligned cracks reported in the literature. While Mode I crack behaviors usually dominate when two parallel non-aligned cracks co-exist, Mode II crack behaviors could dominate in the cases of the slanted crack affected by a horizontal crack. At the same time, depending on how the previously mentioned parameters interact, both Mode I and II SIFs compete with each other, with neither one negligible, in many specific scenarios.