PSI - Issue 33

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Procedia Structural Integrity 33 (2021) 1042–1054

© 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the IGF ExCo Abstract Transverse cracking is commonly experienced by fiber-reinforced composites subjected to multi-axial loading, especially for laminates with different ply orientations. This microscopic damage mechanism causes a decrease in their overall stiffness properties, and may promote delamination between adjacent plies, which is usually associated with their premature failure. Many works have clearly shown the role of interactions between microscopic and macroscopic damage sources in determining the overall strength properties of such materials, highlighting the need for fully detailed models. However, the huge computational cost of the related numerical simulations has motivated the introduction of different multiscale models for failure analysis of fiber-reinforced composites under transverse loading, using in combination with fracture models to represent fiber/matrix debonding and matrix cracking. Such models, including the popular computational homogenization-based and multilevel domain decomposition-based approaches, allow both damage percolation and boundary layer effects to be adequately captured, but are quite complicated to be implemented within the most common commercial finite element codes. In this work, a simpler although reliable two-scale approach is presented, able to predict in a very accurate and efficient way the transition from diffuse micro-cracking to localized transverse macro-cracks in fiber-reinforced composites. The proposed approach is based on a diffuse cohesive interface model, adopted to derive a microscopically based traction-separation law to be used within a purely homogenized nonlinear model for simulating matrix cracking. Numerical computations are performed with reference to small fiber-reinforced components subjected to complex loading paths. Finally, comparisons with reference solutions obtained via direct numerical simulations are presented to assess the validity of the proposed approach. © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo Keywords: Transverse cracking; Cohesive finite elements; Fiber-reinforced laminates; Micromechanical approach IGF26 - 26th International Conference on Fracture and Structural Integrity Numerical prediction of transverse cracking and delamination in fiber-reinforced laminates by using a two-scale cohesive finite element approach Daniele Gaetano, Fabrizio Greco*, Lorenzo Leonetti, Paolo Lonetti, Paolo Nevone Blasi Department of Civil Engineering, University of Calabria, Via P. Bucci Cubo 39B, Rende 87036, Italy Abstract Transverse cracking is commonly experienced by fiber-reinforced composites subjected to multi-axial loading, especially for laminat with d fferent ply rientations. This microscop c damage echanism causes a decrease in their ov rall stiffness proper i , and may promote delamination between adja ent plies, which is usually associated with th ir premature fai ure. Many w rks have clearly shown th ro e of in eractions between microscopic and macroscopic damage sourc s in d termining th overall strengt prop rties of such materials, highlighting the n ed fo fully detailed models. However, the huge computat o al cost of the related numerical imulations has motivated the in roduction o differ nt multiscale models for failure analysis of fiber-reinf rced composites under transverse lo ding, using in combination with racture models to repr ent fiber/m trix deb nd ng and matrix racking. Such model , including the popular put ti al homogenization-based and mul ilev l domain decomposition-b sed approaches, allow both damage percolation nd boundary l yer effects to be adequately captur d, but are quit complicated to be im lemented within e ost common commercial finite el ment codes. In this work, a simpler although reliab e two-scal ap roach is presented, able to predict i a very a curate and efficient way the tran iti n from diffuse micro-crack ng to localized transverse macro-cracks in fibe -re nforced composites. The proposed pproach i based n a diffuse cohesive interface mod l, adopted to derive a microscopically based traction-separation law to be used within a purely homog nized nonlin ar model for simulating matrix cracking. Numerical computa s are performed with ref rence to small fiber-reinforced compo nts subj cted to complex load ng paths. Finally, comparisons with ref rence solutions obtained via direct nume ical simulations ar present d to assess th validity of the proposed appro ch. © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review Statem nt: Peer-revi w under responsibility of th scientifi committee of the IGF ExCo K ywords: Tr nsverse cracking; Cohesive fin te elements; Fiber-reinforced laminates; Micromechanical approach IGF26 - 26th International Conference on Fracture and Structural Integrity Numerical prediction of transverse cracking and delamination in fiber-reinforced laminates by using a two-scale cohesive finite element approach Daniele Gaetano, Fabrizio Greco*, Lorenzo Leonetti, Paolo Lonetti, Paolo Nevone Blasi Department of Civil Engineering, University of Calabria, Via P. Bucci Cubo 39B, Rende 87036, Italy

* Corresponding author. Tel.: +390984446916. E-mail address: fabrizio.greco@unical.it * Corresponding author. Tel.: +390984446916. E-mail address: fabrizio.greco@unical.it

2452-3216 © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review Statement: Peer-review under responsibility of the scientific committee of the IGF ExCo 2452-3216 © 2021 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review Statement: Peer-revi w under responsibility of the scientifi committee of the IGF ExCo

2452-3216 © 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the IGF ExCo 10.1016/j.prostr.2021.10.116