Activity: Talk or presentation › Oral presentation
We present a new imaging approach to determine porosity in Carbon Fibre Reinforced Polymers by Active Thermography in the reflection mode. The IR-radiation is excited with help of a semiconductor laser. We use rectangular pulses for the excitation light – either single pulses or a sequence of a couple of pulses - and measure the succeeding temperature transients. These signals are transferred to the frequency domain by means of a discrete Laplace transformation. The evaluation of the thermal effusivity is done by a linear fitting process which gives unequivocal results with comparatively small error bars. The method is fast, robust and insensitive to inhomogeneous illumination. The results compare well with prior experiments carried out with ultrasonic-testing, X-Ray-Computed Tomography or other approaches of thermography, where the thermal diffusivity has been determined.