Optimization of flat-oval pipes and perspectives of their application in beam structures

Abstract

A new technical solution for re-profiling round tubes into flat-oval ones with a ratio of 1 / 3,064 is presented, which increases their bending strength. The calculation of the optimal parameters of thin-walled sections of the flat-oval shape is given by an approximate method, the correctness of which is confirmed by testing from the standard profiles used. This calculation is repeated with respect to thin-walled sections of the oval shape. The whole diagram of changes in the design parameters of flat-oval and oval pipes is presented in the transformation of their cross-sections from vertical configurations to horizontal ones, including the transition through the outline of a circular shape. The comparative analysis of optimized cross sections of flat oval, oval and round tubes is carried out taking into account the elastic and elastic-plastic deformations of the structural material, where the length of the midline of the thin-walled section is taken as the dividing line between these deformations. The choice is substantiated in favour of flat-oval profile pipes due to their simpler shape including faces of constant curvature (flat and semi-circular), relatively low cost, lower height, greater compactness, higher resistance moment.