Investigation of Fracture in Polymeric Coatings
Author(s)
Tantideeravit, Soratos
Type
Thesis
Abstract
The objective of this study is to quantify the effect of low amplitude cyclic stresses, such as those
induced by environmental condition fluctuations and transportation, on multilayer paint systems
found in works of art. A model was developed to establish criteria for damage, which take into
account viscoelastic fatigue, and to establish safe rates of change for environmental parameters. To
establish the methodology, the investigation focused on modern paintings executed in mixed media.
In particular, acrylic gesso grounds with superimposed alkyd paint layers on canvas were
investigated, which have been found to be vulnerable to stresses and delamination. Data from
uniaxial testing of free-standing paint films were used to determine the constitutive properties of
the paint. The effects of temperature, strain rate and age on the tensile properties were
investigated. Results from peel tests, performed to determine the energy release rate of the
interface between the paint and gesso layers, are reported.
The peel tests were modelled using Finite Element Analysis with cohesive zone elements at the
interface in a commercial finite element software Abaqus. The value of the maximum traction in the
traction-separation law was determined by comparing numerical and experimental peel loads and
the cohesive energy was determined using an established analytical method. The cohesive zone
properties determined from the peel tests, and the calibrated constitutive model for the alkyd paint,
were used in a separate finite element model of a coating on a primed canvas substrate subjected to
combined cyclic hygrothermal and static mechanical loadings typically experienced by fine art
paintings; interface separation was controlled by an irreversible cohesive zone model that includes
damage accumulation due to cyclic loading. Fatigue crack initiation times in years, and crack
propagation rates, are predicted under various conditions including ordinary and extreme histories
that paintings may experience in museum and conservation settings.
induced by environmental condition fluctuations and transportation, on multilayer paint systems
found in works of art. A model was developed to establish criteria for damage, which take into
account viscoelastic fatigue, and to establish safe rates of change for environmental parameters. To
establish the methodology, the investigation focused on modern paintings executed in mixed media.
In particular, acrylic gesso grounds with superimposed alkyd paint layers on canvas were
investigated, which have been found to be vulnerable to stresses and delamination. Data from
uniaxial testing of free-standing paint films were used to determine the constitutive properties of
the paint. The effects of temperature, strain rate and age on the tensile properties were
investigated. Results from peel tests, performed to determine the energy release rate of the
interface between the paint and gesso layers, are reported.
The peel tests were modelled using Finite Element Analysis with cohesive zone elements at the
interface in a commercial finite element software Abaqus. The value of the maximum traction in the
traction-separation law was determined by comparing numerical and experimental peel loads and
the cohesive energy was determined using an established analytical method. The cohesive zone
properties determined from the peel tests, and the calibrated constitutive model for the alkyd paint,
were used in a separate finite element model of a coating on a primed canvas substrate subjected to
combined cyclic hygrothermal and static mechanical loadings typically experienced by fine art
paintings; interface separation was controlled by an irreversible cohesive zone model that includes
damage accumulation due to cyclic loading. Fatigue crack initiation times in years, and crack
propagation rates, are predicted under various conditions including ordinary and extreme histories
that paintings may experience in museum and conservation settings.
Date Issued
2013-02
Date Awarded
2013-05
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Charalambides, Maria
Balint, Daniel
Sponsor
Thailand
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)