A phase-field formulation for dynamic cohesive fracture

We extend a phase-field/gradient damage formulation for cohesive fracture to the dynamic case. The model is characterized by a regularized fracture energy that is linear in the damage field, as well as non-polynomial degradation functions. Two categories of degradation functions are examined, and a...

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Bibliographic Details
Published in:Computer methods in applied mechanics and engineering 2019-05, Vol.348 (C), p.680-711
Main Authors: Geelen, Rudy J.M., Liu, Yingjie, Hu, Tianchen, Tupek, Michael R., Dolbow, John E.
Format: Article
Language:English
Subjects:
Cohesion
Cohesive fracture
Computer simulation
Crack propagation
Damage
Degradation
Dynamic fracture
ENGINEERING
Fracture toughness
Functions (mathematics)
Gradient models
Mathematical analysis
Mathematical models
Phase-field models
Polynomials
Robustness (mathematics)
Strain
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Summary:We extend a phase-field/gradient damage formulation for cohesive fracture to the dynamic case. The model is characterized by a regularized fracture energy that is linear in the damage field, as well as non-polynomial degradation functions. Two categories of degradation functions are examined, and a process to derive a given degradation function based on a local stress–strain response in the cohesive zone is presented. The resulting model is characterized by a linear elastic regime prior to the onset of damage, and controlled strain-softening thereafter. The governing equations are derived according to macro- and microforce balance theories, naturally accounting for the irreversible nature of the fracture process by introducing suitable constraints for the kinetics of the underlying microstructural changes. The model is complemented by an efficient staggered solution scheme based on an augmented Lagrangian method. Numerical examples demonstrate that the proposed model is a robust and effective method for simulating cohesive crack propagation, with particular emphasis on dynamic fracture. •We develop a regularized model of cohesive fracture with applications to quasi-static and dynamic problems.•A new degradation function is derived and tested.•Options for enforcing irreversibility constraints are examined.•The convergence of the model with decreasing regularization length is examined.
ISSN:0045-7825
1879-2138
DOI:10.1016/j.cma.2019.01.026