A ONE-DIMENSIONAL BEAM MODEL FOR COUPLED INSTABILITIES

摘要

A direct one-dimensional beam model accounting for warping is introduced. The bi-shear and bimoment naturally result as quantities spending power on the warping and its first derivative. Balance of power provides local balance equations. Standard inner constraints are imposed. By means of suitable non linear hyperelastic constitutive equations, two coupled bifurcations for axially loaded beams are examined. Interaction shows that in both cases the beam is sensitive to initial imperfections.