| This talk will describe recent applications of the phase-field method to study the classical three-dimensional instability of a crack front in mixed mode fracture. This instability is characterized by a complex rotation and segmentation of the crack front into partial fronts as an adjustment to tensile and antiplane shear loading. Although this segmentation process is widely observed experimentally, its origin is not understood. Phase-field simulations reveal that segmentation results from a helical instability of the crack front with a preferred pitch. Furthermore, analysis of the phase-field equations highlights how the principle of local symmetry needs to be modified to describe this instability--and more generally crack paths in three dimensions--within the classical theoretical framework of continuum fracture mechanics. |
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