Thermal stress analysis and entropy generation rate due to laser short pulse heating of a metallic surface

An analytical solution is developed for thermal stress in exponentially time decaying laser short-pulse heating of a metallic surface. Because the heating duration is short, a nonequilibrium heating model incorporating the electron kinetic theory approach is used to formulate the temperature distribution during the laser heating pulse. Thermomechanical coupling is introduced in the analysis to formulate the thermal stress field. Thermodynamic irreversibility is considered and the entropy generation rate due to heat transfer and thermal stress field is formulated during the heating process. It is found that temperature decays gradually in the surface region and becomes sharp as the distance increases towards the solid bulk. Thermal stress is compressive in the irradiated region. Thermodynamic irreversibility due to heat transfer dominates thermodynamic irreversibility because of the thermal stress field. PACS No.: 44.10.+i. Nous presentons une solution analytique pour la contrainte thermique due a une impulsion laser a decroissance exponentielle sur une surface metallique. Parce que le chauffage est de courte duree, nous utilisons un modele de chauffage hors d'equilibre incorporant la theorie cinetique des electrons afin de formuler la distribution de temperature pendant l'impulsion laser. L'introduction d'un couplage thermomecanique permet de decrire le champ de contrainte thermique. Nous tenons compte de l'irreversibilite thermodynamique et nous formulons le taux de generation d'entropie du au transfert de chaleur et au champ de contrainte thermique pendant le processus, pour trouver que la diminution de temperature qui est graduelle dans la region du chauffage devient rapide a distance. La contrainte thermique est compressive dans la region du chauffage. L'irreversibilite thermodynamique due au transfert de chaleur est plus importante que celle due a la contrainte thermique. [Traduit par la Redaction]
Introduction Laser short pulse heating of metallic surfaces involves nonequilibrium energy transport in the irradiated region. Electron and lattice subsystems separate thermally because of electron temperature increases through energy absorption [...]