A phase-field formulation for dynamic cohesive fracture

TL;DR

This paper develops a dynamic phase-field model for cohesive fracture that incorporates a linear elastic regime, strain-softening, and an efficient solution scheme, enabling robust simulation of crack propagation in dynamic conditions.

Contribution

It introduces a novel phase-field formulation for dynamic cohesive fracture with specific degradation functions and a macro-microforce balance approach, advancing simulation capabilities.

Findings

Model accurately simulates dynamic crack propagation.

The approach effectively captures strain-softening behavior.

Numerical examples confirm robustness and efficiency.

Abstract

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.