Engineering methodology for checking the local stability of the wall of steel I-beams in distributed stress fields

Abstract

For many years, normative methods have been developed and applied for the core schematic of the calculation of load-bearing structures. With the increase in computing power of computers and the development of computer programs, it becomes possible to consider design situations for the load-bearing structures modeled in three dimensional form. The results of the calculation of mechanical systems of three-dimensional finite element models in computer complexes are presented in the form of distribution fields: stresses, deformations, displacements. Stresses can be distributed on the plane for plate models or in volume for models of volumetric finite elements. For correct work with the results of calculations of three-dimensional computer models, normative methods of calculation need a quality update and adaptation to new levels of design automation. In the paper, discusses the procedure for determining the average stress values in the wall of a finite element model of a steel beam, broken into compartments, while checking local stability. The author calculated the steel I-beam of an overlapping beam with a span of 18 meters in the SCAD Office computing complex. The beam geometry is modeled from finite casing elements with zero Gaussian curvature. The article discusses an example of determining the average stress values in an ordinary beam compartment. In the example, the procedure for determining the average stresses in the wall of the steel beam by the distributed fields for the subsequent substitution of the local stability test into the normative condition is indicated. It is proposed to determine the average values of stresses in proportion to the distribution area in the finite elements along the compartment or section of the compartment, in horizontal rows. In the considered method, it is sufficient to determine the average values of stresses for two horizontal rows, then it is proposed to linearly interpolate or extrapolate the required stress along the height of the cross section. The article proposes an engineering method for testing local stability for use in the practice of design.