A tracking strategy for multi-branched crack tips in phase-field modeling of dynamic fractures

The well-received phase-field method smears the discrete cracks in the damaged bands, blurring the explicit crack tip. However, identifying the location of the crack tip is sometimes vital. The widely used scheme at present considers the forefront of a phase-field contour as the crack tip. Such a method, to our best knowledge, is inapplicable for branched cracks, which motivates us to develop a novel stepwise identification strategy for multi-branched crack tips termed si-MCT. Instead of searching for crack tips globally, the proposed si-MCT realizes this in the chosen deliberately local regions (searching regions), and then automatically updates these regions as the cracks propagate. For the robust implementation of si-MCT, a novel concept of active crack tip zone is also proposed to cope with the extreme circumstances where adjacent crack paths are too close to interfere with identifying the crack tip. Furthermore, the core algorithms and specific procedures of the proposed strategy are also elaborated. Moreover, several representative tests are studied, showing the bright prospect of si-MCT in dynamic multi-branch crack tracking and adaptive mesh algorithm.

Automated summary

si-MCT is a novel strategy for identifying multi-branched crack tips step by step, achieving crack tip identification in deliberately chosen local regions and automatically updating these regions as the cracks propagate. It introduces a new concept of the active crack tip zone to handle extreme circumstances, and has shown promising results in various tests.