在空间遥感领域, 使用胶粘接技术安装光学元件越来越受到光机工程师们的青睐。与机械方法相比, 胶粘接方法具有更轻的质量、更低的成本、更容易装配。大部分结构胶在固化期间存在收缩现象, 结构胶的收缩会导致内应力出现, 内应力又会导致光学表面发生变形, 从而影响成像质量。为了在有限元分析中模拟这一过程, 提出了等效线胀法的概念。该方法是将结构胶的线收缩率等效成胶的线胀系数, 从而将结构胶固化过程的收缩等效成均匀温降导致的冷缩, 以便进行热弹性分析。分析结果表明: 在采用环带粘接方式时, 粘接面积越小, 镜面相应位置的面形误差越小, 反之越大; 粘接位置离镜面越远, 镜面相应位置的面形误差越小, 反之越大。对分析结果进行了试验验证, 结果表明: 当胶层质心到镜面距离为20.5mm、胶层宽度分别为15mm、20mm、25mm时, 镜面PV值变化量分别为0.64λ、0.92λ、1.10λ; 当胶层宽度为15mm、胶层质心到镜面距离分别为15.5mm、20.5mm、25.5mm时, 镜面PV值变化量分别为1.08λ、0.64λ、0.40λ; 当胶层质心到镜面距离为25.5mm、胶层宽度为25mm、胶层环形分布角分别为40°、60°、80°时, 镜面PV值变化量分别为0.38λ、0.52λ、0.88λ。分析和试验结果为实际的工程应用提供了理论指导。

In the field of space remote sensing, adhesive bonding technology for mounting optical components is increasingly favored by opto-mechanical engineers. In contrast to mechanical methods, adhesive bonding method usually results in lighter weight, lower costs and easier assembly. Most structural adhesives will shrink during curing process, the shrinkage may cause internal stress, which will lead to deformation of optical surfaces, and affect the imaging quality. To simulate this process using finite element analysis (FEA), a concept of equivalent linear expansion is proposed. In this method, the linear shrinkage of structural adhesive is equivalent to the coefficient of linear expansion, so the shrink of the adhesive during curing can be thought of a process of contraction resulted from drop of temperature while doing thermal elastic analysis. Analysis results show that: with circular bonding, the smaller the bonding area is, the lower the error of mirror surface is, the farther the bonding location is, the lower the error of mirror surface is. Experiments are conducted to verify the analysis, and the results show that: 1) The variable quantify of surface figure error is 0.64~1.10λ PV while the distance between centroid of bonding layer and mirror surface is 20.5mm and the width of bonding layer is 15 ~ 25mm; 2) The variable quantify of surface figure error is 1.08~0.40λ PV while the width is 15mm and the distance is 15.5~25.5mm; 3) The variable quantify of surface figure error is 0.38~0.88λ PV while the distance is 25.5mm,the width is 25mm,and circular distribution angle of bonding layer is 40°~80°.The method proposed here and the results of analysis and experiments may guide the engineering design of mirrors.