Buckling behavior of built-up thin-walled I-beams with trapezoidal flanged cores

This paper focuses on the stability of thin-walled I-beams with sandwich trapezoidal flanges subjected to a three-point bending test. The flange structure consists of a channel beam flange, a trapezoidal corrugated core, and an external flat metal sheet. The stability of the I-beam was analyzed using two approaches: experimental testing and numerical analysis based on the finite element method (FEM). The experimental tests were conducted for two different methods of joining the flange layers (welding and adhesive bonding), revealing notable differences between the methods, particularly in larger displacements. Strain gauges were applied to the flange and web to measure shear stresses during the three-point test. The numerical FEM analysis determined the critical load values and buckling modes for various beam lengths, while also calculating shear stresses. Additionally, numerical studies of beams with nonsymmetric flanges showed higher critical force values compared to symmetric beams. • Thin walled I-beams with sandwich, trapezoidal flanges. • Finite Element Method buckling study. • Experimental investigation. • Different types of connections. • Built-up section.