Geometrically nonlinear three-noded flat triangular shell elements

This paper provides a novel approach to the geometrically nonlinear analysis of shells by deriving the geometric stiffness matrix by load perturbing the linear equilibrium equations in their finite element formulation. Rotations are considered as finite, and rigid body motion is elegantly removed to result in pure elastic deformations that enable stress retrieval via linear constitutive relations. Simple three-noded triangular elements that have proven successful in linear analysis will thus transform to powerful nonlinear elements.