A Finite Plate Method to Solve Cylinder-to-Cylinder Structures Subjected to Internal Pressure

Abstract

An axisymmetric geometric assumption combined with the use of asymmetric loading conditions is presented as an inexpensive alternative to 3-D geometric stress analysis of a variety of nozzle-to-cylinder structures. The finite plate concept explored by Rodabaugh, is used as the axisymmetric attachment to the nozzle, and both nozzle and plate are idealized by the finite element method. The variable plate parameters are the plate outer radius and the harmonic loading at the outer radius. These parameters are determined by utilizing the shell solution of stresses about a circular hole in a cylinder as data for point matching in a flat plate with a hole. The appropriate plate parameters are determined as a function of the curvature parameter β. Examples comparing 3-D and axisymmetric geometric finite element data are presented which illustrate the method. Finally, a discussion of the applicability and limitations of the method in the analysis of nozzles is presented.