An improved analytical model for the prediction of the nonlinear behavior of flat and curved deployable space frames

Abstract

The deployable space frames investigated in this paper consist of straight bars linked together in the factory as a compact bundle, which can then be unfolded into large-span, load-bearing structural forms. During the deployment process incompatibilities between the member lengths lead to the occurrence of strains and stresses resulting in a snap-through phenomenon that ‘locks’ the structures in their deployed configuration. The structural response during deployment is, therefore, characterized by geometric nonlinearities and hence accurate simulation of the deployment process requires sophisticated finite element modeling. In the present work, three versions of a simple analytical model are proposed that predict the intensity of the snap-through phenomenon based on geometric compatibility considerations. Deployable units for flat roofs or spherical domes are addressed. The objective of this approximation is to minimize the number of required finite element analyses during preliminary design. The proposed analytical model is validated through comparison to numerical results obtained by detailed finite element simulation.