Brittle dynamic fracture response and crack propagation behavior of biomimetic tree-like fractal groove structure

Brittle fracture is one of the most common collapse modes in engineering materials and often leads to sudden and unpredictable structural failure. Although the phase-field method has greatly simplified the simulation of brittle fracture, the effects of groove-type interfacial defects on dynamic fracture behavior are still unclear. Drawing inspiration from fractal biomimetic concept, this study proposes a biomimetic tree-like fractal groove structure (TFGS) that integrates fractal geometry with engineered groove defects. We adopt the dynamic phase-field model to systematically examine how the hierarchical levels and geometric parameters of the TFGS affect the dynamic crack propagation behavior. The coupling mechanisms between dynamic effects and groove-interface characteristics are also explored. Testing results indicate that the groove hierarchy, thickness, angle, and length are all the key parameters for regulating the dynamic crack propagation path. By practicing these parameters, the TFGS can effectively trigger crack deflection, branching or acceleration, thereby altering the dynamic fracture characteristics, such as crack-tip velocity, elastic strain-energy storage, and fracture-energy dissipation. These findings reveal the relationship between dynamic fracture mechanisms and multi-level groove structures. They also provide new insights for the structural design of engineered materials and offer a promising pathway toward precise crack-path control and optimized fracture performance.