Thermoelastic/Ablatic Laser Generated Ultrasound in Graphite/Polymer Composites Detected with a Cfp-Based System in Reflection Configuration

A laser-based system was used to study thermoelastic (TE) and ablative (AB) ultrasonic generation mechanisms in graphite/polymer composites. When laser pulses of sufficiently low energy are incident on the sample, elastic waves are generated by the thermal expansion which accompanies absorption of the laser energy. At higher amplitudes, where the laser energy is high enough to melt and vaporize material in the sample, elastic waves are also generated by an ablative process. Thermoelastic and ablative ultrasound generation are described in the literature [1]. A review article by Srinivasan [2] includes excellent photographs of ablation of pure polymers