Phase-field fracture modeling for creep crack

Creep cracks will significantly impact the structure's safety under high temperatures. Currently, most phase-field models describe the creep crack growth by considering the viscous strain energy as a part of the driving force. This work proposes a phase-field model for creep crack in elasto-plastic materials with a different approach. A creep degradation function of creep strain acting on fracture toughness is introduced to describe the effect of creep on crack growth. And it is modified with a function of stress triaxiality to consider the effect of multiaxial stress. Several numerical examples are simulated to validate the presented model. In addition, some parametric studies are performed for different element sizes, length scales, and creep parameters.