An efficient phase field solver for modelling of elastic–plastic fracture in bimaterials

In this work, the phase-field framework coupled with J2 plasticity is expressed in the variational formulation to simulate the bimaterial interfacial problems. The quadratic energetic degradation function in conjunction with the AT2 model is employed for phase-field regularization. A load increment-independent and computationally efficient Staggered scheme is proposed to solve the phase field problems. The existing unconditionally stable quasi-Newton-based Monolithic scheme, which captures the cracking in brittle solids has been extended to capture the crack evolution in the elastoplastic solids using the return mapping algorithm. A Generalized user-defined element subroutine (UEL) is developed and implemented in the commercial software ABAQUS using the proposed Staggered and Monolithic schemes. The efficacy of the proposed algorithms was validated against existing literature and extended to study bimaterials with interfaces. Different geometry and loading configurations in the bimaterial and their interface are modeled using the phase-field framework and analyzed using proposed schemes. The contour plots of phase field for crack evolution, equivalent plastic strain, and reaction force are presented. The efficacy of proposed algorithms in terms of the total number of iterations and the computational CPU time is provided for all numerically simulated cases.