Local buckling of thin-walled fibre composite beams under transverse loading

Plate structures are often subjected to differential compression due to non uniform bending during their service life. In practice, most beams are subj ected to transverse loads that create moment gradient; the resulting loadin g system for such beams is a combination of longitudinal stress gradient wi th associated shearing and transverse stresses. This paper presents a theor etical view of elastic local instability of anisotropic composite beams whi ch are treated as assemblies of symmetric angle-ply composite plates buckli ng under nonlinear varying, uniaxial compressive forces. Uniformly distribu ted load and central concentrated load are two common loading systems actin g on simply supported, wide-flange I-section beams. The Galerkin method is applied to the resulting plate equilibrium equations. The present study sho ws that the buckling load obtained from the proposed approach for composite flanges is greater than that obtained by existing solutions. Results also show that for beams subjected to the uniformly distributed load loading sys tem, local buckling may be initiated in the web, especially for short-span deep beams. However, under the central concentrated load loading system, th e compressive flange limits buckling strength.