Nonlinear Elastic Nonuniform Torsion

Abstract

This paper is concerned with large twist rotations of elastic thin-walled open section beams that induce additional longitudinal stresses, which exert nonlinear “Wagner” stiffening torques. The nonlinear behavior of a narrow rectangular beam is first analyzed and then extended to elastic beams of general cross section. Expressions are derived for the nonlinear Wagner section constants for narrow rectangular sections, doubly symmetric I sections, and monosymmetric equal angle sections. A general finite element method of analyzing nonlinear torsion is described, and used to develop a computer program