活塞激光热负荷就是通过光学转光片改变激光在空间的能量分配比例。结合活塞激光热负荷试验工况,建立了活塞激光热负荷应力场模拟数学物理模型,模型中考虑了材料的热物性参数随温度的变化。结果表明:由于活塞顶凹坑位置靠近通油孔,导致其应力波动幅值比激光辐照区域大;活塞凹坑、通油孔和靠近活塞顶面的活塞内腔由于和冷却介质直接接触,是活塞激光热负荷易损伤区域。试验验证了活塞易损伤区域与数值模拟一致,说明了模型的有效性。

To accomplish laser thermal loading of piston,space intensity distribution of laser is changed by diffractive optical element (DOE). Numerical simulation model of stress field of laser thermal loading is established with considering the experimental condition. In the model, temperature dependent of thermal physical properties are taken into account. Results show that the rate of stress oscillation on the concave region of top surface of piston is larger than that of laser irradiation region due to concave region near tunnel. Meanwhile these regions of concave, tunnel and inner chamber is most vulnerable to form crack due to cool medium contact with them. The results of experiment are agree with numerical simulation, which show numerical simulation model is right.