Shear buckling of channel sections with simply supported ends using the Semi-Analytical Finite Strip Method

• The Semi-Analytical Finite Strip Method (SAFSM) is used for the analyses.
• The new restrained SAFSM buckling theory in shear allows multiple buckle half-waves.
• Channel sections in pure shear with both plain and longitudinally stiffened webs are studied.
• Solutions are checked against the Spline Finite Strip Method (SFSM).

Buckling of thin-walled sections in pure shear has been recently investigated using the Semi-Analytical Finite Strip Method (SAFSM) to develop the “signature curve” for sections in shear. The method assumes that the buckle is part of an infinitely long section unrestrained against distortion at its ends. For sections restrained at finite lengths by transverse stiffeners or other similar constraints, the Spline Finite Strip Method (SFSM) has been used to determine the elastic buckling loads in pure shear. These loads are higher than those from the SAFSM due to the constraints.The SFSM requires considerable computation to achieve the buckling loads due to the large numbers of degrees of freedom of the system. In the 1980s, Anderson and Williams developed a shear buckling analysis for sections in shear where the ends are simply supported based on the exact finite strip method. The current paper further develops the SAFSM buckling theory of Y.K. Cheung for sections in pure shear accounting for simply supported ends using the methodology of Anderson and Williams. The theory is applied to the buckling of plates of increasing length and channel sections in pure shear also for increasing length. The method requires increasing numbers of series terms as the sections become longer. Convergence studies with strip subdivision and number of series terms is provided in the paper.