望远镜主镜支撑中粘接连接的热应力研究

Reserch on the Thermal Stress of Bond Connentcion Used in Telescope Primary Mirror Support Systerm

支撑与镜面的连接是大型望远镜主镜支撑的关键技术之一,连接的好坏直接影响望远镜的成像质量。相比机械紧固方式,粘接连接具有重量轻、成本低、易于装配等优点,常被用来作为支撑和主镜的连接方式。但由于粘接连接中镜子和粘接层的材料不同,在温度变化时,会引起较大的热应力,从而影响主镜的面形质量,因此对粘接链接中的热应力也需要进行研究。为此本文使用有限元方法对粘接层的热应力进行了系统研究,采用了MMT望远镜的支撑结构形式,通过计算镜子表面热应力分布情况,找到热应力最大值,并研究了几何因素、粘接层厚度和粘接层模量对热应力最大值的影响。

Ther connection technology of support syterm and primary mirror is one of the key technologies of larger Telscope.The connection can derectly effect the telescope image quality.Compared with the mechnical conncetion, the bond connection is lighter, cheaper and easier to fix.So it is used to connect the mirror and support sysyterm frequently. While as the materials of mirror and bond layer is different, there will be a strong thermal stress when the temperature changing.And the thermal stress will affect the mirror image quality.So the thermal strees of bond connection should be studied deeply.In this article, the thermal stress of bond connection was studied systermly by using finte element analy- sis method （FEM） .The support systerm of Mutiply mirror telescope （MMT） was borrowed to be analyzied.As the maxmum of thermal stress directlty affected the safety of the mirror.The maxmum of the thermal stress was got by computing the distribution of thermal stress.And the influence of the geometry factor, bound module and bound thick- ness to the maxmum of thermal stress was studied.