AN IMPROVED ANALYTICAL MODEL FOR THE PREDICTION OF THE NONLINEAR BEHAVIOR OF FLAT AND CURVED DEPLOYABLE SPACE FRAMES

The deployable space frames investigated in this paper consist of stra ight bars linked together in the factory as a compact bundle, which ca n then be unfolded into large-span, load-bearing structural forms, Dur ing the deployment process incompatibilities between the member length s lead to the occurrence of strains and stresses resulting in a snap-t hrough phenomenon that 'locks' the structures in their deployed config uration. The structural response during deployment is, therefore, char acterized 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 ba sed on geometric compatibility considerations. Deployable units for pa t roofs or spherical domes are addressed, The objective of this approx imation 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 el ement simulation. (C) 1997 Elsevier Science Ltd.