非球面玻璃透镜模压成型的有限元应力分析

Stress Analysis of Compression Molding of Aspherical Glass Lenses Using Finite Element Method

针对玻璃镜片模压成型过程中无法获得精确的内部残余应力数据,本文提出使用有限元方法分析内应力变化历程及预测残余应力分布。该方法根据高温下玻璃性质近似于粘弹性材料,将五单元广义Maxwell模型的蠕变响应并入有限元计算。采用高级非线性有限元程序MSC.Marc,分别对圆柱玻璃单轴压缩和非球面透镜模压成型进行了仿真,获得了玻璃镜片成型后的残余应力分布情况。在此基础上,文章重点分析了温度和模压速度对合模后镜片内部残余应力分布的影响。实验结果表明,最大应力出现在镜片的边缘区域;较低的温度和较高的模压速度都会增大最大残余应力值。

Accurate data of the internal residual stress can not be obtained in the process of compression molding of aspherical glass lenses, so finite element method was presented to analyze inner stresshistory and predict residual stress distribution. According to the nature of glass at high temperatures which is similar to viscoelastic material, the creep response of 5-pairs general Maxwell model is incorporated into the finite element numerical calculation. Using advanced nonlinear finite element program of MSC.Marc, uniaxial compression of cylindrical glass and compression molding of aspherical glass lenses were simulated. Residual stress distribution in lenses compressed is obtained. On the basis of above mentioned, the effect of temperature and molding velocity on residual stress distribution in lenses was importantly analyzed. The experimental result shows that maximum residual stress occurs at the edge of the lens, and lower temperature and higher molding speed will increase the maximum residual stress.