Nonlinear Analysis of Space Trusses

A mixed method and a computational procedure are presented for the analysis of pin-jointed trusses in the presence of both geometric and material nonlinearities. The problem is formulated in terms of both internal forces and joint displacements and the governing equations consist of the two sets of joint equilibrium equations and member force-displacement (constitutive) relations. Analysis is focused on the advantages of the mixed method over the traditional force and displacement methods, as well as on means of further improving the computational efficiency of the mixed method. The paper concludes with numerical examples showing application of the mixed method to nonlinear problems of plane as well as space trusses subjected to proportional loading. The constitutive relations in these examples are assumed, for convenience, to be represented by the Ramberg-Osgood polynomials.