Theoretical Analysis of Suspension Roofs

The finite deflection theory analysis of a spatial system of nets on the basis of nonlinear theory and a more accurate representation of the material's stress-strain relationship is presented. The structures considered comprise cables and truss members which are assumed incapable of resisting bending. The theory is valid regardless of the magnitude of the displacements as long as the stresses are within the elastic limits. An actual stress-strain curve is used for members stressed beyond the proportional limit. A derivation is given for the tangent stiffnes matrix of a space structure at a state of deformation. The joint equations of equilibrium are transformed into linear equations at any intermediate state of deformation, and a solution tangent to the load-deflection curve is obtained. The displacements are determined by means of an iterative technique. The analysis is given for three problems: (1) Cable; (2) prestressd suspension roof; and (3) truss stressed beyond the proportional limit.