连续激光辐照锗材料损伤的数值模拟研究

Numerical analysis of CW laser damage in Germanium

以热传导理论和热弹应力理论为基础,建立了连续平顶激光辐照锗材料的二维非稳态物理模型。对受辐照锗材料的热-力场分布进行数值模拟,比较了激光辐照时间对靶材热-力场分布的影响,探讨了温度场及应力场空间梯度随半径的分布以及激光辐照时间对热-力场空间梯度的影响。计算结果表明,靶材中心温升效应最大,而应力最大值出现在光斑半径外侧;光斑边缘处温度场和应力场梯度绝对值均达到最大,随着辐照时间的延长,材料同一点温度场和应力场梯度均增大。在给定条件下,计算了靶材的损伤时间,应力损伤域值最先达到。

A two-dimensional transient physical model of flat-topped laser irradiation Germanium was established based on heat conduction theory and thermoelastic dynamic theory.The thermodynamic field of the irradiated material was simulated to compare the thermodynamic field differences at different irradiation times.The distribution of temperature field and stress field gradients along radius was discussed,as well as the impact of irradiation time on the distribution.The calculation results show that the greatest temperature rise effect occurs at the center of target material,and the temperature goes up as the irradiation time extends,moreover,stress field peak occurs outside the spot radius.The temperature and stress field gradients reach maximum values at the spot edge,and the longer the irradiation time,the greater the temperature and stress fields gradients at a fixed point.Under the given conditions,the damage time of subject material was calculated,and the stress damage threhold was reached first.