Phase-field modelling of failure in hybrid laminates

Alessi, Roberto; Freddi, Francesco

doi:10.1016/j.compstruct.2017.08.073

Cited by 59 publications

(29 citation statements)

References 66 publications

(83 reference statements)

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“…Let us just mention a few works, among many others concerning fiber-reinforced composites, which proposed damage continuum mechanics models at the mesoscopic ply level [39][40][41][42]. Phase-field models have also been used to simulate the unidimensional behavior of hybrid laminates, including a competition between fracture of both layers and debonding of the adhesive interface [43].…”

Section: Introductionmentioning

confidence: 99%

Phase-field modeling of anisotropic brittle fracture including several damage mechanisms

Bleyer

Alessi

2018

Computer Methods in Applied Mechanics and Engineering

180

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The present paper aims at modeling complex fracture phenomena where different damaging mechanisms are involved. For this purpose, the standard one-variable phase-field/gradient damage model, able to regularize Griffith's isotropic brittle fracture problem, is extended to describe different degradation mechanisms through several distinct damage variables. Associating with each damage variable a different dissipated fracture energy, the coupling between all mechanisms is achieved through the degradation of the elastic stiffness. The framework is very general and can be tailored to many situations where different fracture mechanisms are present as well as to model anisotropic fracture phenomena. In this first work, after a general presentation of the model, the attention is focused on a specific paradigmatic case, namely the brittle fracture problem of a 2D homogeneous orthotropic medium with two different damaging mechanisms with respect to the two orthogonal directions. Illustrative numerical applications consider propagation in mode I and II as well as kinking of cracks as a result of a transition between the two fracture mechanisms. It is shown that the proposed model and numerical implementation compares well with theoretical and experimental results, allowing to reproduce specific features of crack propagation in anisotropic materials whereas standard models using one damage variable seem unable to do so.

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Section: Introductionmentioning

confidence: 99%

Phase-field modeling of anisotropic brittle fracture including several damage mechanisms

Bleyer

Alessi

2018

Computer Methods in Applied Mechanics and Engineering

180

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“…As a final step, let us argue that any TOL rec ≤ 0.01 may be taken as a practical recovery threshold. For this, we substitute (58) in F a (r) = 3 16r 2 L − 2 , thus yielding…”

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confidence: 99%

“…With r opt given by (58), the relation (54) is used for computing the actual penalty parameter ρ for the corresponding penalized recovery formulation:…”

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confidence: 99%

On penalization in variational phase-field models of brittle fracture

Gerasimov

Lorenzis

2019

Computer Methods in Applied Mechanics and Engineering

125

131

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Irreversible evolution is one of the central concepts as well as implementation challenges of both the variational approach to fracture by Francfort and Marigo (1998) and its regularized counterpart by Bourdin, Francfort and Marigo (2000and 2008, which is commonly referred to as a phase-field model of brittle fracture. Irreversibility of the crack phase-field imposed to prevent fracture healing leads to a constrained minimization problem, whose optimality condition is given by a variational inequality. In our study, the irreversibility is handled via penalization. Provided the penalty constant is well-tuned, the penalized formulation is a good approximation to the original one, with the advantage that the induced equality-based weak problem enables a much simpler algorithmic treatment. We propose an analytical procedure for deriving the optimal penalty constant, more precisely, its lower bound, which guarantees a sufficiently accurate enforcement of the crack phase-field irreversibility. Our main tool is the notion of the optimal phase-field profile, as well as the Γ-convergence result. It is shown that the explicit lower bound is a function of two formulation parameters (the fracture toughness and the regularization length scale) but is independent on the problem setup (geometry, boundary conditions etc.) and the formulation ingredients (degradation function, tension-compression split etc.). The optimally-penalized formulation is tested for two benchmark problems, including one with available analytical solution. We also compare our results with those obtained by using the alternative irreversibility technique based on the notion of the history field by .

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“…Furthermore, the finite element implementation is straightforward in both two and three dimensions, using the classical FEM without any modification of initial meshes or shape functions. Examples of phase field models adopted for simulating fracture and damage in composite materials can be found, for example, in [103][104][105].…”

Section: Phase Field Methodsmentioning

confidence: 99%

Linear and Nonlinear Dynamic Analyses of Sandwich Panels with Face Sheet‐to‐Core Debonding

Burlayenko

2018

Shock and Vibration

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A survey of recent developments in the dynamic analysis of sandwich panels with face sheet-to-core debonding is presented. The finite element method within the ABAQUS6 code is utilized. The emphasis is directed to the procedures used to elaborate linear and nonlinear models and to predict dynamic response of the sandwich panels. Recently developed models are presented, which can be applied for structural health monitoring algorithms of real-scale sandwich panels. First, various popular theories of intact sandwich panels are briefly mentioned and a model is proposed to effectively analyse the modal dynamics of debonded and damaged (due to impact) sandwich panels. The influences of debonding size, form, and location and number of such damage incidents on the modal characteristics of sandwich panels are shown. For nonlinear analysis, models based on implicit and explicit time integration schemes are presented and dynamic responses gained with those models are discussed. Finally, questions related to debonding progression at the face sheet-core interface when dynamic loading continues with time are briefly highlighted.

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Phase-field modelling of failure in hybrid laminates

Cited by 59 publications

References 66 publications

Phase-field modeling of anisotropic brittle fracture including several damage mechanisms

Phase-field modeling of anisotropic brittle fracture including several damage mechanisms

On penalization in variational phase-field models of brittle fracture

Linear and Nonlinear Dynamic Analyses of Sandwich Panels with Face Sheet‐to‐Core Debonding

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