Ritz solution for buckling analysis of thin walled composite channel beams based on a classical beam theory

The displacement field is based on classical beam theory. Both plane stress and plane strain state are used to achieve constitutive equations. The governing equations are derived from Lagrange’s equations. Ritz method is applied to obtain the critical buckl. ing loads of thin-walled beams. Numerical results are compared to those in available literature and investigate the effects of fiber angle, length-to-height’s ratio, boundary condition on the critical buckling loads of thin-walled channel beams