The effect of ply folds as manufacturing defect on the fatigue life of CFRP materials

Manufacturing defects are inherent to any manufacturing process. However, in composite materials they might be unavoidable, e.g. ply waviness or even folds of plies are present in complex shaped parts during high pressure resin transfer molding of carbon fiber reinforced polymers. In this work, the...

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Main Authors: S. Hörrmann, A. Adumitroaie, M. Schagerl
Format: Article
Language:English
Published: Gruppo Italiano Frattura 2016-10-01
Series:Fracture and Structural Integrity
Subjects:
Online Access:http://www.gruppofrattura.it/pdf/rivista/numero38/numero_38_art_10.pdf
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author S. Hörrmann
A. Adumitroaie
M. Schagerl
author_facet S. Hörrmann
A. Adumitroaie
M. Schagerl
author_sort S. Hörrmann
collection DOAJ
description Manufacturing defects are inherent to any manufacturing process. However, in composite materials they might be unavoidable, e.g. ply waviness or even folds of plies are present in complex shaped parts during high pressure resin transfer molding of carbon fiber reinforced polymers. In this work, the effect of the ply folds on the fatigue life of the composite material is investigated. Folds along fiber direction (as they commonly appear during manufacturing) were artificially introduced in unidirectional non crimp fabric plies. The target of this study is the prediction of damage initiation due to this particular type of manufacturing defect. The folds locally increase the fiber volume fraction and also introduce resin rich areas. Fatigue tests in fiber direction and transverse to fiber direction are performed at different load ratios under constant amplitude loading. The influence of the defect geometry on damage initiation and progression is investigated at different scales by non-destructive methods before testing, continuous strain measurement and monitoring the damage progression during testing and fractography analysis after final failure. Most of the time, the first damage was observed at the location of the introduced fold for all considered load cases. However, it was also found, that the folds lead to no significant reduction in fatigue life
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institution Kabale University
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1971-8993
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series Fracture and Structural Integrity
spelling doaj-art-d97a324061cb47f5ae8a528ff45797982025-01-02T22:37:57ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89931971-89932016-10-011038768110.3221/IGF-ESIS.38.10 The effect of ply folds as manufacturing defect on the fatigue life of CFRP materialsS. Hörrmann0 A. Adumitroaie1 M. Schagerl 2Johannes Kepler University Linz,AustriaJohannes Kepler University Linz,AustriaJohannes Kepler University Linz,AustriaManufacturing defects are inherent to any manufacturing process. However, in composite materials they might be unavoidable, e.g. ply waviness or even folds of plies are present in complex shaped parts during high pressure resin transfer molding of carbon fiber reinforced polymers. In this work, the effect of the ply folds on the fatigue life of the composite material is investigated. Folds along fiber direction (as they commonly appear during manufacturing) were artificially introduced in unidirectional non crimp fabric plies. The target of this study is the prediction of damage initiation due to this particular type of manufacturing defect. The folds locally increase the fiber volume fraction and also introduce resin rich areas. Fatigue tests in fiber direction and transverse to fiber direction are performed at different load ratios under constant amplitude loading. The influence of the defect geometry on damage initiation and progression is investigated at different scales by non-destructive methods before testing, continuous strain measurement and monitoring the damage progression during testing and fractography analysis after final failure. Most of the time, the first damage was observed at the location of the introduced fold for all considered load cases. However, it was also found, that the folds lead to no significant reduction in fatigue lifehttp://www.gruppofrattura.it/pdf/rivista/numero38/numero_38_art_10.pdfManufacturing defectsCFRPFatigue damageFold
spellingShingle S. Hörrmann
A. Adumitroaie
M. Schagerl
The effect of ply folds as manufacturing defect on the fatigue life of CFRP materials
Fracture and Structural Integrity
Manufacturing defects
CFRP
Fatigue damage
Fold
title The effect of ply folds as manufacturing defect on the fatigue life of CFRP materials
title_full The effect of ply folds as manufacturing defect on the fatigue life of CFRP materials
title_fullStr The effect of ply folds as manufacturing defect on the fatigue life of CFRP materials
title_full_unstemmed The effect of ply folds as manufacturing defect on the fatigue life of CFRP materials
title_short The effect of ply folds as manufacturing defect on the fatigue life of CFRP materials
title_sort effect of ply folds as manufacturing defect on the fatigue life of cfrp materials
topic Manufacturing defects
CFRP
Fatigue damage
Fold
url http://www.gruppofrattura.it/pdf/rivista/numero38/numero_38_art_10.pdf
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