Direct Stiffness Solution for Folded Plates

A solution for the analysis of a prismatic folded plate with arbitrary boundary conditions along the longitudinal joints or folds is presented. A direct stiffness method in matrix form is used with the individual plates taken as structural elements. The imposed conditions may consist of any combination of known joint loads and displacements. The solution yields results for the unknown joint displacements and reactions, as well as values of longitudinal plate stresses, transverse moments, membrane and normal shears, and transverse membrane forces. Application of both the ordinary and the elasticity theory in the development of the element stiffness matrix is given. A computer program written for the IBM 7090 computer is described, and results obtained using ordinary theory and elasticity theory are compared.