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Title: Electrical characterisation of aerospace grade carbon-fibre-reinforced polymers
Author: Abid, Rabia
ISNI:       0000 0004 5915 2439
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2015
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This thesis is primarily concerned with experimental tests and computer simulations to determine electrical characteristics of carbon fibre composites used in aerospace. The work has involved an extensive review of published literature, numerical modelling and experimental findings on electrical characterization of carbon fibre composites. The numerical modelling on carbon composites was carried out using finite element package COMSOL, using preliminary conductivity values from literature. Lightning impulse waveform D was used, on a surface electrode to study the effect of lightning strike on carbon composites. Existence of shared equi-potentials was found. Low current testing using variable ply lay ups of carbon composites was performed, the resistance measurements were taken using two probe method for volume conductivity, these values were compared and complied well with the values in literature. Surface resistance was also measured using new techniques, which introduced material and contact resistance into the parasitic resistance, the measurements of parasitic resistance gave an accurate measure of current distortion in variable ply layups. The current distortion was more transverse to the fibre direction and less in line to the fibre direction. High current testing was performed using high voltage system in Cardiff high voltage lab, this was done for two current ranges Amperes and kA range. For both current ranges the samples were tested for mechanical strength requirements keeping in mind the mechanical design requirements for aircraft designers, it was found that the mechanical strength for samples impact with lightning impulse was not effected in Amperes range however it starts to effect in kA range at 11 kA. Thermal damage in carbon composites was viewed under the scanned electron microscope using continuous current injection into a carbon composite sample obtained from a T joint. The sample microstructure showed that the fibres have splits and cracks along their diameters which shows that the direct current will be quite damaging to carbon fibres and will disrupt their electrical network.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TA Engineering (General). Civil engineering (General)