PSI - Issue 14

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2018) 000 – 000 Available online at w w w .sciencedirect.com ScienceDirect Available online at w w w .sciencedirect.com ScienceDirect

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ScienceDirect Structural Integrity Procedia 00 (2018) 000 – 000

Procedia Structural Integrity 14 (2019) 849–854

2nd International Conference on Structural Integrity and Exhibition 2018 Effect of hygrothermal aging on the interlaminar shear strength of a carbon fibre composite 2nd International Conference on Structural Integrity and Exhibition 2018 Effect of hygrothermal aging on the interlaminar shear strength of a carbon fibre composite

Kishora Shetty a, *, Shylaja Srihari a,b , CM Manjunatha a,b a Academy of Scientific and Innovative Research (AcSIR), Ghaziabad - 201002, India b CSIR-National Aerospace Laboratoires, Bangalore - 560017, India Kishora Shetty a, *, Shylaja Srihari a,b , CM Manjunatha a,b a Academy of Scientific and Innovative Research (AcSIR), Ghaziabad - 201002, India b CSIR-National Aerospace Laboratoires, Bangalore - 560017, India

Abstract Abstract

© 2019 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/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. t rs. lis lse i r . . T i is a ss rt i l er t C B - - li ( t t s://creat ivecom ons.org/licenses/by-nc-nd/4.0/) Select io p r-r vi er r p i ilit f Pe r-r i er r s sibilit f the I 18 r ni rs. Carbon Fibre Reinforced Plast ic (CFRP) composites are used many applicat ions in aerospace st ructures due to their high specif ic st rength and st iffness. Composite aircraft st ructures are usually exposed to a range of environmental condit ions such as hygroth ermal, UVradiat ion, chemical environment s, biological condit ion etc., in their service life and may degrade. Moisture absorpt ion at different hygrotherma l condit ions and it s effect s on propert ies of CFRP composites is a useful parameter to designers and applicat ion engineers. In this study, UD carbon fiber/epoxy composite laminates were fabricated (HexPly®M21E/34%/UD/194/IMA) from prepreg using standard autoclave process. Inter Laminar Shear St rength (ILSS) test specimens were cut and prepared from theses laminates. Hot -wet specimens were aged at two different condit ions; 75 0 C/ 85% RH, 55 0 C/ 100% RH unt il at taining moisture absorpt ion saturat ion. Three-point bend test s were conducted as per ASTM test standard specificat ions using a 25 KN servo-hydraulic test machine to determine ILSS propert ies for aged and unaged material. Respect ive hot -wet condit ions were maintained even during the mechanical test s. Tests result s show that moisture absorpt ion rate increases gradually and at tains saturat ion at about 1 wt . % under both condit ions. Inter laminar shear st rength reduced significant ly by about 33% due to presence of moisture. Microscopic observat ion of failed samples also invest igated to study the fracture behavior and reported in this paper. © 2018 The Authors. Published by Elsevier B.V. This is an open access art icle under the CC BY-NC-ND license (ht tps://creat ivecommons.org/licenses/by-nc-nd/4.0/) Select ion and peer-reviewunder responsibility of Peer-reviewunder responsibility of the SICE 2018 organizers. Carbon Fibre Reinforced Plast ic (CFRP) composites are used many applicat ions in aerospace st ructures due to their high specif ic st rength and st iffness. Composite aircraft st ructures are usually exposed to a range of environmental condit ions such as hygroth ermal, UVradiat ion, chemical environment s, biological condit ion etc., in their service life and may degrade. Moisture absorpt ion at different hygrotherma l condit ions and it s effect s on propert ies of CFRP composites is a useful parameter to designers and applicat ion engineers. In this study, UD carbon fiber/epoxy composite laminates were fabricated (HexPly®M21E/34%/UD/194/IMA) from prepreg using standard autoclave process. Inter Laminar Shear St rength (ILSS) test specimens were cut and prepared from theses laminates. Hot -wet specimens were aged at two different condit ions; 75 0 C/ 85% RH, 55 0 C/ 100% RH unt il at taining moisture absorpt ion saturat ion. Three-point bend test s were conducted as per ASTM test standard specificat ions using a 25 KN servo-hydraulic test machine to determine ILSS propert ies for aged and unaged material. Respect ive hot -wet condit ions were maintained even during the mechanical test s. Tests result s show that moisture absorpt ion rate increases gradually and at tains saturat ion at about 1 wt . % under both condit ions. Inter laminar shear st rength reduced significant ly by about 33% due to presence of moisture. Microscopic observat ion of failed samples also invest igated to study the fracture behavior and reported in this paper. © 8

Keywords: Composite; Hygrothermal; Inter Laminar Keywords: Composite; Hygrothermal; Inter Laminar

1. Introduction 1. Introduction

Carbon Fibre Reinforced Plastic (CFRP) composites are used in a wide range of applications from sports equipment to aerospace structures due to lower weight with high strength and stiffness – Kishora et al. (2016), Yuichiro et al. (2008). Use of composite materials in Aircraft is increasing day by day. Composite aircraft structures are usually exposed to a range of environmental conditions like hygrothermal, UVradiation, chemical environments, biological condition etc., in their service life. This effect composite material properties includingdegradation. Thedegradation includes mainly chemical changes of thematrix materials and de-bonding at fibre/matrix interface. Moisture absorption at different hydrothermal conditions and its effects on Carbon Fibre Reinforced Plastic (CFRP) composites are used in a wide range of applications from sports equipment to aerospace structures due to lower weight with high strength and stiffness – Kishora et al. (2016), Yuichiro et al. (2008). Use of composite materials in Aircraft is increasing day by day. Composite aircraft structures are usually exposed to a range of environmental conditions like hygrothermal, UVradiation, chemical environments, biological condition etc., in their service life. This effect composite material properties includingdegradation. Thedegradation includes mainly chemical changes of thematrix materials and de-bonding at fibre/matrix interface. Moisture absorption at different hydrothermal conditions and its effects on

* Corresponding author. Tel.: +91-9886676333; fax: +91-80-25270076. E-mail address: kishora_shetty@yahoo.com * Corresponding author. Tel.: +91-9886676333; fax: +91-80-25270076. E-mail address: kishora_shetty@yahoo.com

2452-3216  2019 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/) Selection and peer-review under responsibility of Peer-review under responsibility of the SICE 2018 organizers. 10.1016/j.prostr.2019.07.063 2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is an open access art icle under the CC BY-NC-ND license (ht tps://creat ivecommons.org/licenses/by-nc-nd/4.0/) Select ion and peer-reviewunder responsibility of the SICE 2018 organizers. 2452-3216 © 2018 The Authors. Published by Elsevier B.V. This is an open access art icle under the CC BY-NC-ND license (ht tps://creat ivecommons.org/licenses/by-nc-nd/4.0/) Select ion and peer-reviewunder responsibility of the SICE 2018 organizers.