On inner shearing constraints for a direct beam model coarsely describing warping

Abstract

We investigate inner shearing constraints for a direct one-dimensional beam model coarsely de- scribing warping. In particular, we study how they af- fect the field equations for the elastic buckling of open thin-walled beams. We show that the distinction be- tween the axes of the shear centres and of the centroids is crucial for the kinematics of the beam, and to derive expression of reactive actions, hence of buckling criti- cal conditions. We also show how a suitable definition of the warping inertial action and properly introduced inner shearing constraints yield the field equations of the literature for the beam in a general dynamic set- ting.