Analysis and prediction of transition length in circular thin shell deployable booms

Abstract

Coilable thin shell booms are components of deployable space structures, where the transition from a locally flattened state to the recovered circular cross section governs the extent of geometric disturbance along the boom. This study investigates the transition length of circular thin shell booms using finite element modelling, experimental validation and analytical prediction. Numerical models were developed in Abaqus to examine the influence of boom length, radius and wall thickness. Experimental tests using UPVC tubes showed good agreement with the predicted cross-sectional deformation profiles. The results indicate that transition length becomes independent of boom length once sufficient length is available for complete recovery, while increasing radius increases transition length and increasing wall thickness reduces it. A reduced analytical model based on ovalisation, membrane stretching and circumferential bending was developed and reproduced the observed geometric trends. The proposed model provides a basis for estimating transition length in circular deployable booms.