A 3-D CHAIN ALGORITHM WITH PSEUDO-RIGID-BODY MODEL ELEMENTS

A chain algorithm element is created from pseudo-rigid-body segments and used in a chain calculation that accurately predicts the force deflection relationship of beams with large 3-D deflections. Each chain element is made up of three superimposed pseudo-rigid-body models acting orthogonally in relation to each other. The chain algorithm can accurately and quickly predict large displacements and the force-deflection relationship of lateral torsional buckled beams. This approach is not intended to compete with finite element analysis, but rather is a supplement tool that may prove particularly useful in the early phases of design when many analysis iterations are required. The 3-D chain algorithm is demonstrated and compared to the finite element analysis for the nonlinear large-deflection, post-buckling path of a flexible beam undergoing lateral-torsional buckling.