| Popis: |
The aim of the present study is to characterize the variations of thermal resistances between liners and engine blocks of cars; a non-destructive evaluation is proposed: photothermal infrared thermography. The thermal response of the sample submitted to a modulated optical stimulation is measured by means of an infrared camera. Then, a numerical lock-in procedure yields both amplitude and absolute phase maps of the thermal field periodic component. On the one hand, an analytical modelling, associated with an inverse procedure using the Gauss-Newton parameter estimation method, allows the identification of the thermal resistance on academic samples, representative of the liner-engine block interface. On the other hand, the implementation of a numerical modelling allows studying two-dimensional defects at the cast iron-aluminium interface. Finally, the method is applied to liner-engine block interfaces. The measured thermal resistances match the values obtained when a cast iron plate and an aluminium plate are pressed together. |
