STUDY ON LOCAL BUCKLING OF WEBS OF COMPOSITE BEAMS SUBJECTED TO POSITIVE BENDING MOMENT

Before studying the local buckling of webs of composite beams subjected to positive bending moment, the buckling interaction formulas of a simply supported rectangular plate subjected to combinations of tension, bending and shear stresses should be established. The interaction formulas of elastic buckling of such a plate are obtained through the energy method. The results are in an excellent agreement with those obtained from commercial finite element software ANSYS. A simple formula is then presented. Based on the interaction formula, the elastic limiting height-to-thickness ratio is given, which is also compared with the ratio without considering bending and tension. It is demonstrated that the height-to-thickness ratio obtained is increased, and in most cases, it is more than 30% larger. Results obtained provide a good foundation for the research of elasto-plastic buckling of webs of composite beams considering residual stress and initial imperfection.