Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 10) Show all publications
Di Stasio, L., Varna, J. & Ayadi, Z. (2019). Effect of the proximity to the 0°/90° interface on Energy Release Rate of fiber/matrix interface crack growth in the 90°-ply of a cross-ply laminate under tensile loading. Journal of composite materials
Open this publication in new window or tab >>Effect of the proximity to the 0°/90° interface on Energy Release Rate of fiber/matrix interface crack growth in the 90°-ply of a cross-ply laminate under tensile loading
2019 (English)In: Journal of composite materials, ISSN 0021-9983, E-ISSN 1530-793XArticle in journal (Refereed) Submitted
Abstract [en]

Models of Representative Volume Elements (RVEs) of cross-ply laminates with different geometric configurations and damage states are studied. Debond growth is characterized by the estimation of the Mode I and Mode II Energy Release Rate (ERR) using the Virtual Crack Closure Technique (VCCT). It is found that the presence of the 0°/90° interface and the thickness of the 0° layer have no effect, apart from laminates with ultra-thin 90° plies where it is however modest. The present analysis support the claim that debond growth is not affected by the plythickness effect.

Keywords
Polymer-matrix Composites (PMCs), Fibre/matrix bond, Debonding, Finite Element Analysis (FEA)
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-76253 (URN)
Available from: 2019-10-05 Created: 2019-10-05 Last updated: 2019-11-08
Di Stasio, L., Varna, J. & Ayadi, Z. (2019). Energy release rate of the fiber/matrix interface crack in UD composites under transverse loading: Effect of the fiber volume fraction and of the distance to the free surface and to non-adjacent debonds. Theoretical and applied fracture mechanics (Print), 103, Article ID 102251.
Open this publication in new window or tab >>Energy release rate of the fiber/matrix interface crack in UD composites under transverse loading: Effect of the fiber volume fraction and of the distance to the free surface and to non-adjacent debonds
2019 (English)In: Theoretical and applied fracture mechanics (Print), ISSN 0167-8442, E-ISSN 1872-7638, Vol. 103, article id 102251Article in journal (Refereed) Published
Abstract [en]

The effects of crack shielding, finite thickness of the composite and fiber content on fiber/matrix debond growth in thin unidirectional composites are investigated analyzing Representative Volume Elements (RVEs) of different ordered microstructures. Debond growth is characterized by estimation of the Energy Release Rates (ERRs) in Mode I and Mode II using the Virtual Crack Closure Technique (VCCT) and the J-integral. It is found that increasing fiber content, a larger distance between debonds in the loading direction and the presence of a free surface close to the debond have all a strong enhancing effect on the ERR. The presence of fully bonded fibers in the composite thickness direction has instead a constraining effect, and it is shown to be very localized. An explanation of these observations is proposed based on mechanical considerations.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Polymer-matrix Composites (PMCs), Thin-ply, Energy Release Rate, Debonding, Finite Element Analysis (FEA)
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-75072 (URN)10.1016/j.tafmec.2019.102251 (DOI)000489191500024 ()2-s2.0-85066800172 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-27 (johcin)

Available from: 2019-06-27 Created: 2019-06-27 Last updated: 2019-11-08Bibliographically approved
Di Stasio, L., Varna, J. & Ayadi, Z. (2019). Estimating the average size of fiber/matrix interface cracks in UD and cross-ply laminates. In: A. Turon, P. Maimi, M. Fagerström (Ed.), : . Paper presented at 7th ECCOMAS Conference of the Mechanical Response of Composites (COMPOSITES 2019).
Open this publication in new window or tab >>Estimating the average size of fiber/matrix interface cracks in UD and cross-ply laminates
2019 (English)In: / [ed] A. Turon, P. Maimi, M. Fagerström, 2019Conference paper, Published paper (Refereed)
Abstract [en]

Initiation and propagation of fiber/matrix interface cracks are analyzed in Representative Volume Elements (RVEs) of UD and cross-ply laminates. By studying the distribution of stresses at the fiber/matrix interface in the undamaged case, an estimate of the initial flaw size is derived. By adopting a 2-parameters energy-based criterion for propagation [1], we then proceed to the estimation of the expected debond size in different microstructural arrangements. Finally, the results are compared with microscopic observations available in the literature [2].

Keywords
Fiber Reinforced Polymer (FRP), Debonding, Linear Elastic Fracture Mechanics (LEFM)
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials; Polymeric Composite Materials; Polymeric Composite Materials; Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-76254 (URN)
Conference
7th ECCOMAS Conference of the Mechanical Response of Composites (COMPOSITES 2019)
Available from: 2019-10-05 Created: 2019-10-05 Last updated: 2019-11-08
Di Stasio, L. & Ayadi, Z. (2019). Finite Element solution of the fiber/matrix interface crack problem: Convergence properties and mode mixity of the Virtual Crack Closure Technique. Finite elements in analysis and design (Print), 167, Article ID 103332.
Open this publication in new window or tab >>Finite Element solution of the fiber/matrix interface crack problem: Convergence properties and mode mixity of the Virtual Crack Closure Technique
2019 (English)In: Finite elements in analysis and design (Print), ISSN 0168-874X, E-ISSN 1872-6925, Vol. 167, article id 103332Article in journal (Refereed) Published
Abstract [en]

The bi-material interface arc crack has been the focus of interest in the composite community, where it is usually referred to as the fiber-matrix interface crack. In this work, we investigate the convergence properties of the Virtual Crack Closure Technique (VCCT) when applied to the evaluation of the Mode I, Mode II and total Energy Release Rate of the fiber-matrix interface crack in the context of the Finite Element Method (FEM). We first propose a synthetic vectorial formulation of the VCCT. Thanks to this formulation, we study the convergence properties of the method, both analytically and numerically. It is found that Mode I and Mode II Energy Release Rate (ERR) possess a logarithmic dependency with respect to the size of the elements in the crack tip neighborhood, while the total ERR is independent of element size.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Fiber/matrix interface crack, Bi-material interface arc crack, Linear Elastic Fracture Mechanics (LEFM), Virtual Crack Closure Technique (VCCT), Mode separation, Convergence
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-76252 (URN)10.1016/j.finel.2019.103332 (DOI)2-s2.0-85072852081 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-10-07 (johcin)

Available from: 2019-10-05 Created: 2019-10-05 Last updated: 2019-11-08Bibliographically approved
Di Stasio, L., Varna, J. & Ayadi, Z. (2019). Growth of interface cracks on consecutive fibers: on the same or on the opposite sides?. Paper presented at 12th International Conference on Composite Science and Technology (ICCST 12). Materials Today: Proceedings
Open this publication in new window or tab >>Growth of interface cracks on consecutive fibers: on the same or on the opposite sides?
2019 (English)In: Materials Today: Proceedings, E-ISSN 2214-7853Article in journal (Refereed) Submitted
Abstract [en]

The growth of fiber/matrix interface cracks (debonds) locatedon consecutive fibers along the through-the-thickness (vertical)direction is studied in glass fiber-epoxy UD composites. Debonds couldappear, along the vertical direction, on the same or on opposite sides oftheir respective fibers. Determining which configuration is the mostenergetically favorable to debond growth is the objective of this paper.To this end, two different families of Representative Volume Elements(RVEs) are developed: the first implements the classic condition ofcoupling of the vertical displacements to model a unit cell repeating symmetrically along the vertical direction; the second uses a novel setof boundary conditions, proposed here by the authors, to represent a unitcell repeating anti-symmetrically along the vertical direction. The modelis analyzed in the context of Linear Elastic Fracture Mechanics (LEFM)and the Mode I and Mode II Energy Release Rate are evaluated toinvestigate crack growth. The calculation is performed using the VirtualCrack Closure Technique (VCCT) in the framework of the Finite ElementMethod (FEM). It is found that Mode I dominated propagation is favoredwhen debonds are located on the same sides of their respective fibers;while for larger (Mode II-dominated) debonds, Mode II ERR is higher whenthey lie on the opposite sides. No interaction effect is present when atleast two fully bonded fibers are located between the partially debonded ones.

Keywords
Polymer Matrix Composite (PMC), Fracture mechanics, Debonding, Debond Interaction
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-76255 (URN)
Conference
12th International Conference on Composite Science and Technology (ICCST 12)
Available from: 2019-10-05 Created: 2019-10-05 Last updated: 2019-11-08
Di Stasio, L. (2019). Influence of microstructure on debonding at the fiber/matrix interface in fiber-reinforced polymers under tensile loading. (Doctoral dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Influence of microstructure on debonding at the fiber/matrix interface in fiber-reinforced polymers under tensile loading
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2019
Keywords
Fiber/matrix interface, Debonding, Polymer-Matrix Composites (PMC), Finite Element Method (FEM), Linear Elastic Fracture Mechanics (LEFM)
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-76646 (URN)978-91-7790-496-0 (ISBN)978-91-7790-497-7 (ISBN)
Public defence
2019-12-13, E632, E-Huset, Luleå University of Technology, Luleå, 08:30 (English)
Opponent
Supervisors
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-08Bibliographically approved
Di Stasio, L., Varna, J. & Ayadi, Z. (2019). Investigation of Scaling Laws of the Fiber/Matrix Interface Crack in Polymer Composites through Finite Element-based Micromechanical Modeling. In: Book of abstracts of the 10th EEIGM International Conference on Advanced Materials Research: . Paper presented at 10th EEIGM International Conference on Advanced Materials Research - April 25-26, 2019 - Moscow, Russia. Moscow, Russia
Open this publication in new window or tab >>Investigation of Scaling Laws of the Fiber/Matrix Interface Crack in Polymer Composites through Finite Element-based Micromechanical Modeling
2019 (English)In: Book of abstracts of the 10th EEIGM International Conference on Advanced Materials Research, Moscow, Russia, 2019Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Moscow, Russia: , 2019
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-73928 (URN)
Conference
10th EEIGM International Conference on Advanced Materials Research - April 25-26, 2019 - Moscow, Russia
Available from: 2019-05-13 Created: 2019-05-13 Last updated: 2019-09-06
Di Stasio, L., Varna, J. & Ayadi, Z. (2018). Effect of boundary conditions on microdamage initiation in thin ply composite laminates. In: : . Paper presented at ECCM18 - 18 th European Conference on Composite Materials, Athens, Greece, 24-28 th June 2018.
Open this publication in new window or tab >>Effect of boundary conditions on microdamage initiation in thin ply composite laminates
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

The Energy Release Rate (ERR) and the contact zone size for a fiber/matrix interface debond are studied for a thin-ply glass fiber/epoxy laminate. The main objective is to analyze the effect on the debonding process of the presence of a traction-free specimen surface or an adjacent material, in the form of a stiffer UD ply or by considering it as part of a thick 90° layer, at different levels of fiber content. To this end, a model of Representative Volume Element (RVE) subjected to different combinations of boundary conditions is proposed. It is found that the constraining effect of the adjacent ply favors at high fiber volume fractions the opening of small debonds (10 − 40°) for the same level of strain. The results agree well and provide a mechanical explanation to previous microscopic observations available in the literature [4].

Keywords
Polymer-matrix Composites (PMCs), Thin-ply, Transverse Failure, Debonding, Finite Element Analysis (FEA)
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-71656 (URN)
Conference
ECCM18 - 18 th European Conference on Composite Materials, Athens, Greece, 24-28 th June 2018
Available from: 2018-11-19 Created: 2018-11-19 Last updated: 2019-01-21Bibliographically approved
Di Stasio, L., Varna, J. & Ayadi, Z. (2017). Micromechanical modeling of thin ply effects on microdamage in Fiber Reinforced Composite laminates. In: Book of abstracts: . Paper presented at International Materials Research Meeting of the Greater Region - April 6-7, 2017 - Saarbrücken, Germany. Saarbrücken, Germany
Open this publication in new window or tab >>Micromechanical modeling of thin ply effects on microdamage in Fiber Reinforced Composite laminates
2017 (English)In: Book of abstracts, Saarbrücken, Germany, 2017Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Saarbrücken, Germany: , 2017
Keywords
Representative Volume Elements, Micromechanical Modeling, Thin Ply Effect
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-73921 (URN)
Conference
International Materials Research Meeting of the Greater Region - April 6-7, 2017 - Saarbrücken, Germany
Available from: 2019-05-13 Created: 2019-05-13 Last updated: 2019-09-06
Di Stasio, L., Varna, J. & Ayadi, Z. (2017). Micromechanical models of transverse cracking in ultra-thin Fiber-Reinforced Composite laminates. In: : . Paper presented at Séminaire de l'école doctorale EMMA 2017.
Open this publication in new window or tab >>Micromechanical models of transverse cracking in ultra-thin Fiber-Reinforced Composite laminates
2017 (English)Conference paper, Poster (with or without abstract) (Other academic)
Keywords
Representative Volume Elements, Micromechanical Modeling, Thin Ply Effect
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-73920 (URN)
Conference
Séminaire de l'école doctorale EMMA 2017
Available from: 2019-05-13 Created: 2019-05-13 Last updated: 2019-09-06
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-9261-301x

Search in DiVA

Show all publications