PSI - Issue 18

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 18 (2019) 484–489

25th International Conference on Fracture and Structural Integrity Application of a cohesive-zone zig-zag theory to the modeling of mode II dominant delaminations in laminated composites Roberta Massabò*, Hossein Darban Department of Civil, Chemical and Environmental Engineering, University of Genova, Via Montallegro 1, 16145 Genova, Italy Abstract Delamination fracture of layered beams is studied using a homogenized structural model. The model applies local enrichments to the displacement field of a classical equivalent single layer theory in order to (i) better describe the effects of the layered structure on global and local fields and (ii) account for the presence of delaminations, while avoiding the through the thickness discretization of the problem. A homogenization technique is applied and equilibrium equations are derived which depend on only three global displacement variables for any numbers of layers and delaminations. Single and multiple delamination fracture in bend beams is studied using only in-plane discretization. The results are compared with accurate 2D solutions and experiments showing the capability of the homogenized model to predict energy release rate in layered systems, follow unstable crack growth and capture the effects of the interaction of multiple delaminations. 25th International Conference on Fracture and Structural Integrity Application of a cohesive-zone zig-zag theory to the modeling of mode II dominant delaminations in laminated composites Roberta Massabò*, Hossein Darban Department of Civil, Chemical and Environmental Engineering, University of Genova, Via Montallegro 1, 16145 Genova, Italy Abstract D lamin tion fracture f layered beams is studied using a homogenize structural model. The mod l applies local enrichments to the displacement field of classical equivalent single layer theory i order to (i) better describe the effects of the layered structure n global and local fields a d (ii) account for the presence of delaminations, while avoiding the through the thickness discretization of the problem. A homogenization technique is applied and equilibrium equations are deriv d which depend on only three global displaceme t variables for any numbers of lay rs and delaminations. Single and multiple delamination fracture i bend beams is studied using only in-plane iscretization. The results are compared with accurate 2D solutio s and experiments showing th capability of t e homogenized odel to predict energy release rate in layered systems, follow unstable crack growth and capture the effects of the interaction of multiple delaminations.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: delamination fracture; composites; structural theories; homogenization. Keywords: delamination fracture; composites; structural theories; homogenization.

1. Introduction Progressive delamination fracture of laminated composites and layered structures is typically modelled using the finite element method and cohesive-interface elements. This approach requires a fine discretization in the in-plane and through-thickness directions in order to accurately model onset and growth of delaminations at the various interfaces between the layers. This complicates the model layout and increases computational costs, especially since the problem 1. Introduction Progressive delamination fracture of laminated composites and layered structures is typically modelled using the finite element method and cohesive-interface elements. This approach requires a fine discretization in the in-plane and through-thickness directions in order to accurately model onset and growth of delaminations at the various interfaces between the layers. This complicates the model layout and increases computational costs, especially since the problem

* Corresponding author. Tel.:+39 010 353 2956. E-mail address: Roberta.massabo@unige.it * Correspon ing author. Tel.:+39 010 353 2956. E-mail address: Roberta.massabo@unige.it

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.190