Double-phase-field formulation for mixed-mode fracture in rocks

By F. Fei, Jinhyun Choo. Computer Methods in Applied Mechanics and Engineering, 2020

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Cracking of rocks and rock-like materials exhibits a rich variety of patterns where tensile (mode I) and shear (mode II) fractures are often interwoven. These mixed-mode fractures usually involve microcracking and frictional sliding. Nevertheless, computational models that can efficiently simulate a combination of cohesive and frictional fractures remain scarce. In this work, we develop a double-phase-field formulation that employs two different phase fields to describe cohesive tensile fracture and frictional shear fracture individually. The formulation rigorously combines the two phase-fields through three approaches: (i) crack-direction-based decomposition of the strain energy into the tensile, shear, and pure compression parts, (ii) contact-dependent calculation of the potential energy, and (iii) energy-based determination of the dominant fracturing mode in each contact condition. The proposed model is validated, both qualitatively and quantitatively, with experimental data on mixed-mode fracture in rocks. A standout feature of the double phase-field model is that it can simulate, and naturally distinguish between, tensile and shear fractures without complex algorithms.

Subfields: Mechanics of Materials, Ocean Engineering

View Paper: https://www.semanticscholar.org/paper/79515d3dd12b86636f9ec3020c6a1f3e1772b9e8