3-DIMENSIONAL NONLINEAR-ANALYSIS OF ELASTIC ARCHES

This paper presents a curved finite element model for the three-dimens ional nonlinear analysis of elastic arches. The model includes higher- order curvatures which make the order of the bending strains consisten t with that of the membrane strains, and the same low-order polynomial s are used for all the displacements, No approximations are made for t he twist rotations, and the nonlinear strains and the incremental stif fness matrix include the exact coupling due to the twist rotations. Al l significant terms of strains are retained. Without these terms, supe rimposed rigid body motions may lead to overstiff solutions. The model also includes warping of the cross-section and the Wagner effect. App lication of the model to several numerical examples and comparison wit h the existing experimental and analytical results demonstrate that th e model is much more effective and efficient than other methods in ter ms of accuracy, the number of elements needed for convergence, and the ability to pass maximum load points. The model is also used to invest igate the elastic flexural-torsional buckling and the elastic postbuck ling behaviour of arches.