Infrared thermography applied to the prediction of structural vibration behaviour

Abstract

This paper concerns the development of methodology for use of Infrared thermography (IRT) for online prediction of mechanical structural vibration behaviour; given that it has extensively been applied in non-destructive technique for evaluation of surface cracks through the observation of thermal imaging of the vibration-induced crack heat generation. To achieve this, AISI 304 steel cantilever beam coupled with a slipping friction rod was subjected to a forced excitations with an infrared camera capturing the thermal profile at the friction interface. The analysis of thermal image data recorded (radiometric) for the frictional temperature time domain waveform using a MATLAB FFT algorithm in conjunction to IR camera frequency resolution of 120Hz and the use of the heat conduction equation with the help of a finite difference approach successfully identified the structural vibration characteristics in terms of frequency and displacement, the maximum relative errors being 0.09% and 5.85% for frequencies and displacements, respectively. These findings are particularly useful in overcoming many limitations inherent in some of the current vibration measuring techniques in harsh and remote environments. Keywords: Structural health monitoring, Frictional temperature evolution, Online monitoring, Thermal imaging