Thermal/Mechanical Interaction in Laser Perforation Process: Numerical-Model Buildup and Parametric Study

In this paper, a generic thermal/mechanical interaction model was developed to predict the penetration rate and mechanical damage around perforation tunnels that resulted from the laser perforation of rock samples. The perforating process is driven by heat emitted by a laser beam directed at the surface of a sample. The temperature propagation, thermal expansion, and thermal/mechanical interaction were modeled by coupling heat conduction in solid media with the elastic/plastic constitutive mechanical response of rocks. The phase changes that occur during the melting and evaporating process were accounted for in the latent heat of fusion and of vaporization. The heating boundary was updated dynamically along with the evolution of perforation channels. The model was used to parametrically investigate the effects of material properties, stress ratio, and laser-beam characteristics on the penetration rate and mechanical damage.