Abstract:
This thesis investigates the smart damage sensing capabilities of the electrical resistivity
measurement technique in carbon fibre reinforced composite materials.
The static and fatigue damage mechanisms of unidirectional and cross-ply laminates are
reviewed. The electrical resistivity measurement investigations of carbon fibre, epoxy resin and
carbon fibre reinforced composites are described. Theoretical models related to damage and
electrical conduction modelling are reviewed. The material properties, laminate fabrication,
specimen design, tab design and electrode design details are presented. The experimental test
set-up and test programme details are presented.
The details of the formulation and algorithms of a proposed new random resistor network model
and the three-dimensional unit cell assemblage model are described. The results related to the
applicability and the validation of these models are presented.
The influence of electrode effects on the electrical resistance are investigated. The relevant
results are presented. The electrical properties of carbon fibre reinforced composites
independent of specimen geometry and electrode configuration are established. The
dependence of electrical resistance on the specimen geometry was investigated and the
relevant results are presented.
The smart damage sensing capabilities are demonstrated using computational simulation
studies using the proposed new three-dimensional model. The strain sensing and damage
sensing capabilities of electrical resistivity measurement technique under static and fatigue
loading conditions are presented. The dependence of electrical resistance to the applied stress
and fatigue life of the samples subjected to fatigue loading is presented. The smart sensing
capabilities are highlighted based on the experimental and theoretical results.
The static and fatigue behaviour of epoxy 914 and epoxy 920 based CFRP laminates is
investigated. The failure mechanisms are established using the electrical resistance and other
non-destructive test methods.
