Saint-Venant decay rates: A procedure for the prism of general cross-section

Abstract

A procedure previously developed for the determination of decay rates for self-equilibrated loadings at one end of a pin-jointed framework consisting of repeated identical cells, wherein the decay factors are the eigenvalues of the single cell transfer matrix, is here further developed and applied to a prismatic continuum beam of general cross-section. A sectional length of beam is treated within ANSYS finite element code as a super element; nodes at both ends of the section are treated as master nodes and the stiffness matrix relating forces and displacements at these master nodes is constructed within ANSYS. Manipulation of this stiffness matrix within MATLAB gives the transfer matrix from which the eigenvalues and eigenvectors may be readily determined. Accuracy of the method is assessed by treating the plane strain strip, the plane strain sandwich strip, and the rod of circular cross-section, representing a selection of the examples for which exact analytical solutions are available, and is found to be very good in all cases.