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An assessment of phase field fracture: crack initiation and growth.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Kristensen, Philip K 
Niordson, Christian F 
Martínez-Pañeda, Emilio  ORCID logo  https://orcid.org/0000-0002-1562-097X

Abstract

The phase field paradigm, in combination with a suitable variational structure, has opened a path for using Griffith's energy balance to predict the fracture of solids. These so-called phase field fracture methods have gained significant popularity over the past decade, and are now part of commercial finite element packages and engineering fitness- for-service assessments. Crack paths can be predicted, in arbitrary geometries and dimensions, based on a global energy minimization-without the need for ad hoc criteria. In this work, we review the fundamentals of phase field fracture methods and examine their capabilities in delivering predictions in agreement with the classical fracture mechanics theory pioneered by Griffith. The two most widely used phase field fracture models are implemented in the context of the finite element method, and several paradigmatic boundary value problems are addressed to gain insight into their predictive abilities across all cracking stages; both the initiation of growth and stable crack propagation are investigated. In addition, we examine the effectiveness of phase field models with an internal material length scale in capturing size effects and the transition flaw size concept. Our results show that phase field fracture methods satisfactorily approximate classical fracture mechanics predictions and can also reconcile stress and toughness criteria for fracture. The accuracy of the approximation is however dependent on modelling and constitutive choices; we provide a rationale for these differences and identify suitable approaches for delivering phase field fracture predictions that are in good agreement with well-established fracture mechanics paradigms. This article is part of a discussion meeting issue 'A cracking approach to inventing new tough materials: fracture stranger than friction'.

Description

Keywords

Griffith, finite element analysis, fracture mechanics, phase field fracture

Journal Title

Philos Trans A Math Phys Eng Sci

Conference Name

Journal ISSN

1364-503X
1471-2962

Volume Title

379

Publisher

The Royal Society

Rights

All rights reserved
Sponsorship
EPSRC (via Imperial College London) (EP/R010161/1)
Royal Commission for the 1851 Exhibition