Abstract:
Glass Fiber Reinforced Polymer (GFRP) composites
are being used in wide range of applications since these materials
are less affected by environmental and atmospheric conditions in
addition to its high strength to weight ratio. However, there are
still some concerns about reinforced polymers due to their
manufacturing imperfection or imperfections during their inservice,
such as the presence of surface and sub-surface defects
which effect their performance. InfraRed Thermography (IRT)
shows its potential usage for non-destructive testing and
evaluation (NDT&E) due to its intrinsic testing capabilities such
as remote, whole field, quantitative and qualitative to detect
surface and sub-surface defects. This present work highlights a
spectral reshaping by introducing a Gaussian window on the
captured thermal profile in a frequency modulated thermal wave
imaging and named as Gaussian Windowed Frequency
Modulated Thermal Wave Imaging (GWFMTWI) technique.
Further various multi-transform techniques (time and frequency
domain based) have been introduced in order to test sub-surface
defect detection capabilities in chosen GFRP sample. Comparison
has been made with the non-stationary linear frequency
modulated thermal wave imaging technique in terms of depth
scanning capability. Results obtained from the GWFMTWI
clearly shows better detection potential with improved test
resolution and sensitivity.
