采用ANSYS进行形变-应力模拟。对不同应力状态下的熔石英表面进行三倍频激光损伤测试，结果发现，预加压应力为0~50 MPa时损伤阈值有明显提高的趋势，用应力耦合作用对此给出了解释：0~50 MPa的预加压应力可以降低和抵消激光辐照产生的张应力破坏，大于50 MPa预应力的耦合作用会使得该处机械性能下降，另外，损伤增长在预应力存在时更容易发生。因此，0~50 MPa预加压应力时的表面预应力可以提高熔石英的抗激光辐照能力。

The rear surface defects and impurities of fused silica can absorb the laser irradiation energy strongly, resulting in the high temperature difference and thermal stress. When the thermal stress reaches the tensile strength limit, a brittle rupture will happen in the fused silica. In this study, we preload the rear surface of fused silica to weaken and counteract the damage of the thermal stress by mechanical forces. It can produce continuous changes of the pre-stress. As it is difficult to obtain the stress value in experiment, we measure the central deformation rate to the reverse surface stress distribution and simulate deformation and stress changes by ANSYS. A third harmonic generation laser damage test is utilized to the laser induced damage threshold in different pre-stress conditions. It indicates that the pre-stress 0-50 MPa can improve the laser induced damage threshold obviously, because the 0-50 MPa pre-stress can reduce and counteract the tensile stress produced from the laser irradiation. However, the pre-stress more than 50 MPa can reduce the mechanical properties by coupling effects. The pre-stress 0-50 MPa can increase the laser damage resistance effectively.