Mode I fracture in adhesively-bonded joints: A mesh-size independent modelling approach using cohesive elements
File(s)
Accepted version
Author(s)
Alvarez, D
Blackman, BRK
Guild, FJ
Kinloch, AJ
Type
Journal Article
Abstract
In recent years cohesive elements, coupled with a finite-element analysis (FEA) approach, have become increasingly popular for simulating both delamination in composite materials and fracture in adhesively-bonded joints. However, the industrial application of Cohesive Zone Models to model large and complex structures has been hindered by the requirement of extremely fine meshes along the crack propagation path. In the present work two-dimensional linear and quadratic (i.e. second-order) cohesive elements to model crack initiation and growth have been implemented in Abaqus using a user subroutine. These elements, which have a modified topology that allows a user-defined number of integration points, have been employed to model the fracture response of various mode I test specimens consisting of metallic substrates bonded with a structural film-adhesive. The effects of the mesh-density, element order and number of integration points on the numerical solution have been investigated. Whilst the linear models have shown the typical mesh-size dependent behaviour, the results obtained with their quadratic counterparts have been found to be independent of the element size. Furthermore, it is shown that increasing the number of integration points improves the stability, convergence and smoothness of the solutions. The mesh-size independent response obtained with the quadratic models arises from more accurate simulation of the deformed profile of the substrates and a more accurate calculation of the energy dissipated in the process zone due to damage. Overall, it is demonstrated that the quadratic cohesive-element formulation enables the use of much coarser meshes, resulting in shorter simulation times, and will therefore allow an increase in the industrial application of Cohesive Zone Models.
Date Issued
2013-10-19
Date Acceptance
2013-10-03
Citation
Engineering Fracture Mechanics, 2013, 115, pp.73-95
ISSN
1873-7315
Publisher
Elsevier
Start Page
73
End Page
95
Journal / Book Title
Engineering Fracture Mechanics
Volume
115
Copyright Statement
© 2013, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Subjects
Science & Technology
Technology
Mechanics
Adhesives
Cohesive Zone Modelling
Finite-element analysis
Fracture
Mesh-dependency/mesh-size
DUCTILE CRACK-GROWTH
ZONE MODEL
INTERLAMINAR FRACTURE
NUMERICAL SIMULATIONS
LAMINATED COMPOSITES
AUTOMOTIVE ADHESIVES
DURABILITY BEHAVIOR
TRANSVERSE LOADS
FIBER COMPOSITES
DELAMINATION
Publication Status
Published