Biaxial testing of adhesively bonded composite joints

Debonding has been noted as the main cause of failure in bonded composite assemblies and there have been many studies to characterize the failure models surrounding the complex nature of adhesive bond failure. In this study, the author has fabricated and recycled Glass Fiber Reinforced Polymer (GF...

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Bibliographic Details
Main Author: Yap, Jeanette Xin Yi
Other Authors: Sridhar Idapalapati
Format: Final Year Project (FYP)
Language:English
Published: 2018
Subjects:
Online Access:http://hdl.handle.net/10356/74876
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author Yap, Jeanette Xin Yi
author2 Sridhar Idapalapati
author_facet Sridhar Idapalapati
Yap, Jeanette Xin Yi
author_sort Yap, Jeanette Xin Yi
collection NTU
description Debonding has been noted as the main cause of failure in bonded composite assemblies and there have been many studies to characterize the failure models surrounding the complex nature of adhesive bond failure. In this study, the author has fabricated and recycled Glass Fiber Reinforced Polymer (GFRP) specimens to be joined using epoxy adhesive to perform mixed-mode biaxial loading experiments using a modified Arcan Setup. Three types of adhesive joint profiles were used to test and compare the fracture characteristics of the specimens. ABAQUS® finite element analysis software was then used to simulate the experimental measurements of load-displacement to determine a suitable failure model that could fit the fracture mechanics of the debonding of the specimens through the use of cohesive elements and traction-separation law. It was determined that the quadratic nominal stress failure criterion fitted with power law damage evolution was suitable for the straight profile samples. For the rectangle profile, the failure criterion was only suitable for very low loading angles, however the Benzeggagh and Kenane (BK) mixed mode damage evolution criterion was able to predict crack patterns which the power law damage evolution was not able to. The failure criterion did not fit well for the triangle profile as most stresses were either over or under predicted by both damage evolution criterions. However, for loading angles at 60° and 75°, the power law damage evolution was able to predict peak loads. For the straight and rectangle designs, it was noted that the fracture energies predicted by the failure criterion was suitable for loading angles below 45°. For the triangle profile, the fracture energy was suitable for loading angles at 0°, 15° and 60°.
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spelling ntu-10356/748762023-03-04T18:34:43Z Biaxial testing of adhesively bonded composite joints Yap, Jeanette Xin Yi Sridhar Idapalapati School of Mechanical and Aerospace Engineering DRNTU::Engineering Debonding has been noted as the main cause of failure in bonded composite assemblies and there have been many studies to characterize the failure models surrounding the complex nature of adhesive bond failure. In this study, the author has fabricated and recycled Glass Fiber Reinforced Polymer (GFRP) specimens to be joined using epoxy adhesive to perform mixed-mode biaxial loading experiments using a modified Arcan Setup. Three types of adhesive joint profiles were used to test and compare the fracture characteristics of the specimens. ABAQUS® finite element analysis software was then used to simulate the experimental measurements of load-displacement to determine a suitable failure model that could fit the fracture mechanics of the debonding of the specimens through the use of cohesive elements and traction-separation law. It was determined that the quadratic nominal stress failure criterion fitted with power law damage evolution was suitable for the straight profile samples. For the rectangle profile, the failure criterion was only suitable for very low loading angles, however the Benzeggagh and Kenane (BK) mixed mode damage evolution criterion was able to predict crack patterns which the power law damage evolution was not able to. The failure criterion did not fit well for the triangle profile as most stresses were either over or under predicted by both damage evolution criterions. However, for loading angles at 60° and 75°, the power law damage evolution was able to predict peak loads. For the straight and rectangle designs, it was noted that the fracture energies predicted by the failure criterion was suitable for loading angles below 45°. For the triangle profile, the fracture energy was suitable for loading angles at 0°, 15° and 60°. Bachelor of Engineering (Mechanical Engineering) 2018-05-24T07:29:21Z 2018-05-24T07:29:21Z 2018 Final Year Project (FYP) http://hdl.handle.net/10356/74876 en Nanyang Technological University 114 p. application/pdf
spellingShingle DRNTU::Engineering
Yap, Jeanette Xin Yi
Biaxial testing of adhesively bonded composite joints
title Biaxial testing of adhesively bonded composite joints
title_full Biaxial testing of adhesively bonded composite joints
title_fullStr Biaxial testing of adhesively bonded composite joints
title_full_unstemmed Biaxial testing of adhesively bonded composite joints
title_short Biaxial testing of adhesively bonded composite joints
title_sort biaxial testing of adhesively bonded composite joints
topic DRNTU::Engineering
url http://hdl.handle.net/10356/74876
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