激光破岩过程中激光与岩石相互作用的过程涉及到复杂的三维非稳定传热学问题，利用能量守恒原理，得到了激光破岩的传热方程；基于热应力理论和广义胡克定律，得到激光破岩的应力分布求解公式。通过建立激光破岩的三维有限元模型，对光斑直径为0.2 mm 的5 种不同功率的高斯激光源与砂岩的相互作用过程进行了直接耦合数值仿真分析。研究发现，在设定条件下，对于强度较大的岩石，激光破岩过程中起主要作用的是激光的气化作用；而对于强度较小的岩石，起主要作用的是热应力引起的破碎。

In the laser drilling process, the interaction between laser and rock is a complicated three dimensional (3D) unsteady problem. The thermal conduction model is established according to energy conservation equations, and the stress distribution is obtained in accordance with thermal stress theory and generalized Hooke′ s law. Based on the 3D finite element models, the effects of fragmentation and vaporization of malmstone under five kinds of continuous Gaussian distribution lasers with a fixed 0.2 mm spot diameter are estimated. The simulation results are that the primary failure mode of malmstone is vaporization if a specified continuous laser is used to break a rock with a large ultimate strength, however, the primary failure mode of malmstone is fragmentation if a rock has a small ultimate strength.