Elastic critical moment of beams with sinusoidally corrugated webs

This paper approaches the elastic critical moment of web-corrugated beams (WCB), either subjected to a uniform bending moment, gradient bending moments, or a uniformly distributed load. Previous research on the subject of lateral-torsional buckling (LTB) of WCB is presented and critically reviewed. Based on earlier studies on the cross-section properties of beams with trapezoidal corrugations, a new method is proposed to obtain the warping or torsional constant of WCB with sinusoidal corrugation. Furthermore, based on an extensive numerical study for a wide range of different corrugation profiles and lengths, it is demonstrated that the present design formulae for the moment modification factor for flat web beams (FWB) could be improved, in order to predict satisfactorily the buckling capacities of WCB under non-uniform bending distributions. Therefore, a new closed-form expression for the moment modification factor is proposed and successfully verified. Finally, by comparing the analytical results with those obtained from a linear buckling analysis (LBA) carried out using shell finite elements, it is demonstrated that the proposed modifications lead to an accurate prediction of the buckling strength of WCB.