FORM-FINDING OF MEMBRANE STRUCTURES BY DYNAMIC RELAXATION

Stress distribution in membrane structures can be either homogeneous and isotropic resulting in a minimum surface or inhomogeneous and anisotropic resulting in a equilibrium surface.As one of the most frequently used form-finding method for membrane structures,dynamic relaxation features the facility of no need to assemble and solve structure stiffness equations,whereas its defect is the relatively numerous iterations.Dynamic relaxation was modified to accelerate the convergence.During the form-finding procedure the calculating parameters were continuously adjusted according to changing of the structure,and the iteration steps to convergence were greatly reduced as compared with those without parameter adjusting.The excess distortion of elements,which may occur due to omitting of the in-plane shear stiffness and can be overcome by sequential designation of node coordinates.