Analysis of Three Dimensional Thin-Walled Structures

A finite element stiffness analysis is described which can be used for the analysis of arbitrarily shaped folded plate structures or shells. Part I of the paper describes the properties of the elements used, the basis of the solution and an outline of the program procedures. Two alternative elements are used, both being flat and triangular, and with identical in plane properties. They differ in their bending properties, one having cubic displacement variations and not satisfying inter-element compatibility, and the other satisfying compatibility by using linear displacement and slope functions, in which shearing deformations are accounted for. High curvatures, or sharp corners can be accommodated by the allowance for six degrees of freedom at a node. The solution procedures used are described in some detail. Part II describes the application of the program to two examples, one a box girder bridge under bending and torsion, and the other a cylindrical shell subjected to internal pressure.