Equivalent analysis of stacked-core mirrors

Abstract

Stacked-core mirror is fabricated by fusing two faceplates and multiple honeycomb cores with different geometry parameters, which is an effective method to fabricate large aperture, low areal density and high stiffness mirror substrates. To improve design efficiency and simulation accuracy of stacked-core mirrors, two equivalent modeling methods based on equivalent plate method theory and sandwich plate theory were given. Then the dynamic and static analyses were carried out and the results were compared with detailed finite models to analyze the influence of diameterthickness ratio and layer thickness ratio on the accuracy of equivalent methods. The results of both equivalent models in dynamic analyses are obtained with a good accuracy. Error in first frequency increases with the decrease of the diameterthickness ratio and the increase of honeycomb core layer proportion. The results in static analyses show that equivalent models have a good accuracy to symmetry structures when layer thickness ratio changes. Error in static analyses are less than 6% for equivalent plate model and less than 2% for sandwich plate model when diameter-thickness ratio changes. The accuracy of equivalent plate model is lower than that of sandwich plate model in dynamic and static analyses. The equivalent methods discussed in this paper are efficient for stacked-core mirrors’ design and optimization.