A unified phase-field method-based framework for modeling quasi-brittle fracture in composites with interfacial debonding

• Published in: Composite structures 2024-01, Vol.327, p.117647, Article 117647
• Main Authors: Bian, Pei-Liang, Qing, Hai, Schmauder, Siegfried, Yu, Tiantang
• Format: Article
• Language: English
• Subjects: Cohesive zone model; Finite element method; Interfacial debonding; Mixed-mode scheme; Phase-field method
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2023.117647

Interfacial debonding affects the mechanical behaviors of composite structures. In the present work, we developed a new phase-field-based cohesive zone model for modeling debonding at interfaces. The traction-separation law and evolution of phase-field considering the mixed-mode scheme of fracture toughness are given in a variational form. Besides, the present interfacial model can work with the phase-field cohesive zone model for the bulk region, in which a common phase-field value ϕ is shared for both regions. The interaction between the bulk region and interfacial cracking in both displacement, as well as phase-field, are taken into account directly to avoid the over-estimation of the free surface energy. The framework is implemented with the finite element method and validated with several numerical examples. The present work provides a unified approach for modeling quasi-brittle fracture in the bulk region and interfaces and shows its advantage in describing interactions between bulk and interfacial cracking. •A phase-field-based cohesive element is proposed to solve the interfacial failure in composites, where the stiffness, strength, and critical energy release rate can be defined independently in the normal and tangential directions.•The closure effect of the interfacial crack under compression in the normal direction can be modeled with given penalty stiffness.•Governing equation of the interfacial region for the displacement and phase-field is given in a variational form, in which a mixed-mode behavior for a mix of normal and transverse separation is also considered.•The interaction between the interfaces and the bulk region is considered by a crack-driving force, which gives a clear physical meaning to the fracture surface energy at the interface and construct unified framework for simulating fracture in composites.