Crack growth of structural adhesive joints in humid environments
File(s)
Accepted version
Author(s)
Korenberg, CF
Kinloch, AJ
Watts, JF
Type
Journal Article
Abstract
The adhesive fracture energy, G c , of aluminiumalloy and steel joints bonded with a rubber-toughened epoxy adhesive has been measured using monotonicallyloaded tests. Such tests have been conducted at different levels of relative humidity, and two surface pretreatments have been employed for the substrates prior to bonding: a simple grit-blast and degrease (GBD) pretreatment or a silane primer (GBS) pretreatment. When G c was plotted against the crack velocity, three regions of fracture behaviour could be distinguished. At low rates of displacement the crack grew in a stable manner, visually along the interface, and relatively low crack velocities could be readily measured. This was termed “Region I”, and here the value of the adhesive fracture energy was relatively low and decreased steadily as the relative humidity was increased. On the other hand, at relatively high rates of displacement the crack grew in a stick-slip manner mainly cohesively in the adhesive layer at approximately 20 km/min. This was termed “Region III”, and here the value of G c was relatively high and independent of the relative humidity. In this region the crack was considered to grow faster than the water molecules were able to reach the crack tip, which explains the independence of G c upon the test environment. In between Region I and Region III a transition region was observed, which was designated “Region II”. The major effect of the GBS pretreatment, compared to which the GBD pretreatment, was to increase the value of G c both in Regions I and III, although the presence of the silane primer had the greater effect in Region I.
Date Issued
2004-03-01
Date Acceptance
2004-03-01
Citation
Journal of Adhesion, 2004, 80 (3), pp.169-201
ISSN
1545-5823
Publisher
Taylor & Francis
Start Page
169
End Page
201
Journal / Book Title
Journal of Adhesion
Volume
80
Issue
3
Copyright Statement
© 2004 Taylor & Francis. This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Adhesionon 01 Mar 2004, available online at: http://www.tandfonline.com/10.1080/00218460490279233
Subjects
Science & Technology
Technology
Engineering, Chemical
Materials Science, Multidisciplinary
Mechanics
Engineering
Materials Science
ENGINEERING, CHEMICAL
MATERIALS SCIENCE, MULTIDISCIPLINARY
MECHANICS
accelerated testing
durability
environmental attack
fracture mechanics, structural adhesives
RESIN ADHESIVES
FRACTURE
DURABILITY
PMMA
PROPAGATION
INTERFACES
TOUGHNESS
FAILURE
Publication Status
Published