On the energy decomposition in variational phase-field models for brittle fracture under multi-axial stress states


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Date

2024-09

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Phase-field models of brittle fracture are typically endowed with a decomposition of the elastic strain energy density in order to realistically describe fracture under multi-axial stress states. In this contri bution, we identify the essential requirements for this decomposition to correctly describe both nucleation and propagation of cracks. Discussing the evolution of the elastic domains in the strain and stress spaces as damage evolves, we highlight the links between the nucleation and propagation conditions and the modula tion of the elastic energy with the phase-field variable. In light of the identified requirements, we review some of the existing energy decompositions, showcasing their merits and limitations, and conclude that none of them is able to fulfil all requirements. As a partial rem edy to this outcome, we propose a new energy decom position, denoted as star-convex model, which involves a minimal modification of the volumetric-deviatoric decomposition. Predictions of the star-convex model are compared with those of the existing models with different numerical tests encompassing both nucleation and propagation.

Publication status

published

Editor

Book title

Volume

247 (3)

Pages / Article No.

291 - 317

Publisher

Springer

Event

Edition / version

Methods

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Geographic location

Date collected

Date created

Subject

Nucleation; Propagation; Fracture; Multi-axial; Phase-field

Organisational unit

09697 - De Lorenzis, Laura / De Lorenzis, Laura check_circle

Notes

Funding

861061 - New strategies for multifield fracture problems across scales in heterogeneous systems for Energy, Health and Transport (EC)
219407 - Phase-field modeling of fracture and fatigue: from rigorous theory to fast predictive simulations (SNF)

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