Poster #176, Fault and Rupture Mechanics (FARM)

Phase-field modeling of rate- and state-dependent frictional faults

Fan Fei, Md Shumon Mia, Ahmed E. Elbanna, & Jinhyun Choo
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Poster Presentation

2021 SCEC Annual Meeting, Poster #176, SCEC Contribution #11651 VIEW PDF
Handling the complex geometry of discontinuous surfaces is often a formidable challenge in computational simulation of fault rupture. To address this challenge, here we introduce a phase-field approach to the simulation of fault rupture dynamics, which can model arbitrary geometry of discontinuities without representing it explicitly. The method diffusely approximates the discontinuous geometry of a fault introducing the phase-field variable and a carefully designed crack density function, such that it converges to the sharp geometry as the approximation zone becomes thinner. In this way, the phase-field approach allows for topology-free modeling of fault discontinuities, without suffering f...rom problems in existing continuous formulations such as the stress glut method. The proposed approach is built on a phase-field method for frictional interfaces, which was originally formulated for discontinuities with a constant friction coefficient and under quasi-static conditions. For modeling fault rupture dynamics, we extend the formulation to incorporate a rate- and state-dependent friction law with radiation damping, generalizing the existing phase-field method in a novel way. Through simulation of an anti-plane fault rupture problem, we verify that the proposed phase-field approach provides virtually the same results as those obtained by a discontinuous model of the fault solved by a finite element–spectral boundary integral scheme.