Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques

In engineering design, concerns arose on the fatigue behaviours of composite materials.Much effort has been done to estimate the fatigue life by which destructive techniques were commonly used. Recently, non-destructive techniques (NDT) are increasingly being used on composite materials to detect de...

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Main Author:	Mat Jusoh, Suriani
Format:	Thesis
Language:	English
Published:	2012
Subjects:	Kenaf - Technological innovations Kenaf - Thermal properties Fibrous composites - Fatigue
Online Access:	http://psasir.upm.edu.my/id/eprint/64159/1/FK%202012%20156IR.pdf
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spelling	my-upm-ir.641592018-05-30T02:53:35Z Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques 2012-10 Mat Jusoh, Suriani In engineering design, concerns arose on the fatigue behaviours of composite materials.Much effort has been done to estimate the fatigue life by which destructive techniques were commonly used. Recently, non-destructive techniques (NDT) are increasingly being used on composite materials to detect defects. Parallel to the development, shifting interests from traditional monolithic materials to fiber reinforced polymer based materials have been demonstrated by researchers and engineers. Nevertheless, information on the use of NDT on natural fiber reinforced composite materials is still sparse. The present study was set out to detect defects and estimate fatigue life in natural fiber reinforced composite materials. In making the composite, kenaf bast was used as a reinforcement fiber with epoxy as the matrix. The NDT employed to serve the study purposes are Infrared (IR) thermal imaging and optical microscope. In parallel,destructive technique (DT) was also used in this study specifically in carrying out the fatigue tension-tension test and scanning electron microscope (SEM). By and large, the DT was used just to verify all the results by NDT. The advantages of using NDT via IR thermal imaging in kenaf reinforced epoxy composites to estimate the fatigue life are evidenced in the following results: IR has successfully detected five types of manufacturing defects in kenaf reinforced epoxy composites due to manufacturing process. The defects are voids, resin rich area, pockets of undispersed cross-linker, misaligned fiber and regions where resin has poorly wetted the fibers. Subsequently, IR thermal imaging has significantly determined fatigue damage in kenaf reinforced epoxy composites. In addition, fatigue damage modes has also been predicted and determined by the types of defects occurs due to manufacturing process. This proves that IR has successfully been a significant NDT in estimating fatigue life due to fatigue damage, proved experimentally and interpreted by the S-N curve. In terms of fatigue resistance, it is found that 60% fiber volume fraction kenaf reinforced epoxy composites specimen has the highest resistance at 119.71-53.20 MPa. Finally, based on damage accumulation, a model of fatigue life estimation, namely S-IR has been proposed. Kenaf - Technological innovations Kenaf - Thermal properties Fibrous composites - Fatigue 2012-10 Thesis http://psasir.upm.edu.my/id/eprint/64159/ http://psasir.upm.edu.my/id/eprint/64159/1/FK%202012%20156IR.pdf text en public doctoral Universiti Putra Malaysia Kenaf - Technological innovations Kenaf - Thermal properties Fibrous composites - Fatigue
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English
topic	Kenaf - Technological innovations Kenaf - Thermal properties Fibrous composites - Fatigue
spellingShingle	Kenaf - Technological innovations Kenaf - Thermal properties Fibrous composites - Fatigue Mat Jusoh, Suriani Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques
description	In engineering design, concerns arose on the fatigue behaviours of composite materials.Much effort has been done to estimate the fatigue life by which destructive techniques were commonly used. Recently, non-destructive techniques (NDT) are increasingly being used on composite materials to detect defects. Parallel to the development, shifting interests from traditional monolithic materials to fiber reinforced polymer based materials have been demonstrated by researchers and engineers. Nevertheless, information on the use of NDT on natural fiber reinforced composite materials is still sparse. The present study was set out to detect defects and estimate fatigue life in natural fiber reinforced composite materials. In making the composite, kenaf bast was used as a reinforcement fiber with epoxy as the matrix. The NDT employed to serve the study purposes are Infrared (IR) thermal imaging and optical microscope. In parallel,destructive technique (DT) was also used in this study specifically in carrying out the fatigue tension-tension test and scanning electron microscope (SEM). By and large, the DT was used just to verify all the results by NDT. The advantages of using NDT via IR thermal imaging in kenaf reinforced epoxy composites to estimate the fatigue life are evidenced in the following results: IR has successfully detected five types of manufacturing defects in kenaf reinforced epoxy composites due to manufacturing process. The defects are voids, resin rich area, pockets of undispersed cross-linker, misaligned fiber and regions where resin has poorly wetted the fibers. Subsequently, IR thermal imaging has significantly determined fatigue damage in kenaf reinforced epoxy composites. In addition, fatigue damage modes has also been predicted and determined by the types of defects occurs due to manufacturing process. This proves that IR has successfully been a significant NDT in estimating fatigue life due to fatigue damage, proved experimentally and interpreted by the S-N curve. In terms of fatigue resistance, it is found that 60% fiber volume fraction kenaf reinforced epoxy composites specimen has the highest resistance at 119.71-53.20 MPa. Finally, based on damage accumulation, a model of fatigue life estimation, namely S-IR has been proposed.
format	Thesis
qualification_level	Doctorate
author	Mat Jusoh, Suriani
author_facet	Mat Jusoh, Suriani
author_sort	Mat Jusoh, Suriani
title	Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques
title_short	Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques
title_full	Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques
title_fullStr	Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques
title_full_unstemmed	Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques
title_sort	determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and sem techniques
granting_institution	Universiti Putra Malaysia
publishDate	2012
url	http://psasir.upm.edu.my/id/eprint/64159/1/FK%202012%20156IR.pdf
_version_	1747812288365068288

Determination of defects and damage modes in kenaf-reinforced epoxy composites under fatigue loading using thermal imaging and SEM techniques

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