| The objective of this research is to demonstrate and validate the effectiveness of impulse thermography for use in nondestructive testing on Steel-Concrete Composite Structures, and to examine the limitations of impulse thermography with parametric studies. Numerical results from experiments and finite element models were obtained in order to verify the use of thermography for composite structures. This research has shown the effectiveness of impulse thermography, but has displayed that this method of nondestructive testing (NDT) has its limitations. It was found that, the finite element analysis technique can be successfully used to model infrared thermography for nondestructive testing. The finite element model results can reasonably locate defects within concrete specimens; although, when compared to impulse thermography BAM experiment, the surface temperature differences between the BAM model and the BAM experiment had slightly different results. To investigate the effectiveness and limitations of thermography as a form of NDT on Steel-Concrete Composite (SCC) walls, several parameters were studied. The parameters mainly focused on the effects of the change in depths of the defects, heating intensity and heating durations of the analysis. The results of the study demonstrate that defects within the specimen were detectable at certain depths, heating intensities and heating duration. Limitations of the detectability of the defects were seen corresponding to the different parametric cases. This was clearly shown on the finite element infrared thermography models. One of the most evident limitations of detecting defects in the subsurface of the specimen was the depth of the defect. Other parameters such as the duration of the heating and cooling process helped determine characteristics of the defects in the model. For example, longer heating and cooling durations allowed a more definitive thermographic surface image of deeper defects that cannot be seen in shorter time durations. |
