The necking process during deformation of polycarbonate was observed with an infra-red (i.r.) camera. After calibration of the i.r. camera and determination of the emissivity of the sample, it is possible to transform the thermal image into a temperature image. Calculations, based on the heat conduction equation including heat sources and heat loss, yield a quantitative description of the measured temperature pattern and therefore the heat produced by the necking process. The method was checked by comparison with experiments done with a stretching calorimeter. The total balance of energy, heat and work could be measured as a function of the stretching rate. A transition from an increase of internal energy at low strain rates to an unchanged internal energy--all work is converted into heat--at high neck velocities is observed.
Посилання на статтю:
Observation of the heat exchange during deformation using an infra-red camera / Joachim A. Koenen // Polymer. – 1992. – Vol 33. – P. 4732-4736.