Improved stress prediction in adhesive bonded optical components

Adhesives are widely used in optomechanical structures for bonding optical components to their mounts. The main advantage of using adhesives is the excellent strength to weight ratio. Adhesive bonding is seen as a desirable joining technique as it allows for greater flexibility in design. A disadvantage of adhesives however is the limited dimensional stability and loadability. To design stable optical mounts, accurate prediction of stresses and deformation is therefore needed. Adhesives show strong temperature and loading history dependent behavior. Viscoelastic material models are needed for accurate prediction of stresses and strains in bonded joints. However, representative material data for adhesives is difficult to find. In this research, an experimental framework is build up to determine relevant mechanical properties of adhesives for improving stress and deformation prediction. This paper shows the results of the characterization experiments and modeling techniques. Also the implementation of material models in finite element code is briefly discussed. The obtained models are used in the mount design in the EUCLID and TROPOMI programs as described in "Ultra stable isostatic bonded optical mount design for harsh environments, J.A.C.M Pijnenburg et al" (this conference). © 2012 SPIE