Thermal stresses in composite cylindrical lattices

Abstract

Abstract Deployable spacecraft technology should be both lightweight and compact for storage while also being rigid and expansive once deployed. A new type of structure that can meet both of these requirements is the morphing cylindrical lattice. This multi-stable structure can morph from a compact stowed state, to a long and slender deployed beam. It comprises narrow strips of carbon fibre composite material, making it particularly suitable for deployable booms, solar arrays and antennae. While existing modelling techniques focus on predicting the stability of lattices using symmetrical laminates, current work extends upon state-of-the-art by including the effects of thermal strains and curvatures that arise in non-symmetrical laminates when cured at elevated temperatures. As non-symmetrical laminates cool during post-cure, thermal stresses increasingly develop due to the variation of in-plane thermal expansion coefficient through the thickness. The model developed in this work, includes thermal stress effects, allowing for the design of thermally actuating lattices. This model is verified through comparison with finite element analysis and experimental data, both of which show excellent agreement.