PSI - Issue 25

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

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Procedia Structural Integrity 25 (2020) 370–377

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers composit s are prone to creep and stress relaxation. Therefore, the main goal of this w rk is to tudy the hybridization effect on the viscoelastic properties of composites r inforced natural fibres. For this purpose, composites wi h the sam lay-up, but with diff rent fibres (flax and glass fibres), were m nufactur d with a gree epoxy resin. These viscoelastic properties were evaluated in bending mode. It was concluded that, contra y to creep deform ti , tress de r ases with tim , but this tendency is strongly attenuated with the addition of glass fibres. Therefore, the hybridization is n fficient way to decreas the viscoelastic behaviour of natural fibre reinforced composites. Finally, due to the good accuracy obt i ed between th experimenta and theoretic l results, the Kohlrausch-Williams-Watts (KWW) equation and the Findley model can be used to predict stress relaxation time and creep displacement. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers 1st Virtual Conference on Structural Integrity - VCSI1 Hybridization effect on the bending properties of flax composites P. Santos a, *, J.P. Parente a , S. Valvez a , M.P. Silva a , P.N.B. Reis a a C-MAST, Dep. of Electromechanical Engineering, University of Beira Interior, Calçada Fonte do Lameiro, 6201-100 Covilhã, Portugal Abstract Eco-friendly and biodegradable composites are desirable due to the enormous pressure on industry as a result of the air pollution, global warming and the scarcity of fossil fuels. On the other hand, due to inherent viscoelasticity of the matrix phase, polymer composites are prone to creep and stress relaxation. Therefore, the main goal of this work is to study the hybridization effect on the viscoelastic properties of composites reinforced natural fibres. For this purpose, composites with the same lay-up, but with different fibres (flax and glass fibres), were manufactured with a green epoxy resin. These viscoelastic properties were evaluated in bending mode. It was concluded that, contrary to creep deformation, stress decreases with time, but this tendency is strongly attenuated with the addition of glass fibres. Therefore, the hybridization is an efficient way to decrease the viscoelastic behaviour of natural fibre reinforced composites. Finally, due to the good accuracy obtained between the experimental and theoretical results, the Kohlrausch-Williams-Watts (KWW) equation and the Findley model can be used to predict stress relaxation time and creep displacement. 1st Virtual Conference on Structural Integrity - VCSI1 Hybridization effect on the bending properties of flax composites P. Santos a, *, J.P. Parente a , S. Valvez a , M.P. Silva a , P.N.B. Reis a a C-MAST, Dep. of Electromechanical Engineering, University of Beira Interior, Calçada Fonte do Lameiro, 6201-100 Covilhã, Portugal Abstract Eco-friendly and biodegrad ble c mp sites are desirable du to the enorm us pressure on industr as a r sult of the ir pollution, global warming and the scarcity of fossil fuels. O the othe hand, due to inherent viscoelas icity of mat ix phase, polymer 1. Introduction Polymeric matrix composites are very attractive for different engineering applications because they have excellent performances in terms of high specific strength and stiffness, good static and dynamic properties, good resistance to corrosion, adjustable properties, competitive cost and fast manufacture (Fakirov 2015, Reis et al. 2014, Hsu et al. 2018, 1. Introduction P lymeric matrix composites are very attractive for different engineering applications because they have excellent perf rmances in terms f high specific strength and stiffness, good static and dynamic properties, good resistance to corrosion, adjustable properties, competitive cost and fast manufacture (Fakirov 2015, Reis et al. 2014, Hsu et al. 2018, Keywords: Polymer-matrix composites (PMCs); Natural fibers; Hybridization; Viscoelastic behavior. Keywords: Polymer-matrix composites (PMCs); Natural fibers; Hybridization; Viscoelastic behavior.

* Corresponding author. Tel.: 00351 275 319 700. E-mail address: paulo.sergio.santos@ubi.pt * Correspon ing author. Tel.: 00351 275 319 700. E-mail address: paulo.sergio.santos@ubi.pt

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers 2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an ope acces article under C BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Peer-review under responsibility of the VCSI1 organizers

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers 10.1016/j.prostr.2020.04.042