Phase-field Modeling of Anisotropic Brittle Fracture in Fiber-reinforced Composites

Jeremy Bleyer (1) , Roberto Alessi (2)

1 navier umr 8205 - Laboratoire Navier
2 UNIROMA - Università degli Studi di Roma "La Sapienza" = Sapienza University [Rome]

The phase-field approach to fracture is an effective method to describe and simulate complex fracture phenomena and is therefore gaining increasing attention by the computational mechanics community. Many extensions have already been considered ranging from dynamic aspects, plasticity, fluid transport in porous media, finite deformation, etc. However, few works have dealt with anisotropic effects. In particular, these works have considered only an anisotropic fracture energy with an underlying isotropic elastic material. As a result, no work has extended yet the phase-field approach to consider fracture in anisotropic media, in particular fiber-reinforced composites. The present contribution aims at closing this gap by proposing a phase-field approach for brittle fracture in an anisotropic material. In particular, it is shown that standard models including one phase-field variable and possibly an anisotropic fracture energy are not well suited to describe complex crack paths in such materials. Instead, we propose to endow the phase-field energy functional with multiple damage mechanisms, e.g. longitudinal fiber cracking and transverse matrix cracking in the case of fiber-reinforced composites. Although, numerical examples focus on this situation, the proposed framework is sufficiently general to be also applied to all situations where different fracture mechanisms are involved within the same material such as different failure mechanism in tension and compression, fracture anisotropy depending on mode mixity, cracking of composite laminates, etc. Illustrative applications demonstrate that the proposed model is able to capture well known features of crack propagation in fiber-reinforced media such as propagation in the fiber preferential direction, straight propagation under mode II loading but also non trivial behaviors such as crack kinking, whereas a standard phase-field model, even if equipped with an anisotropic fracture energy, is not. Although our work does not focus on an exhaustive description of the complex constitutive behavior of fiber-reinforced composites, we hope that it will contribute to a decisive advance in the development of the phase-field approach for this extremely important class of materials.

Domaines: Matériaux et structures en mécanique [physics.class-ph]

Jeremy Bleyer, Roberto Alessi. Phase-field Modeling of Anisotropic Brittle Fracture in Fiber-reinforced Composites. 13th World Congress on Computational Mechanics (WCCM XIII), Jul 2018, New York, United States. ⟨hal-02434339⟩