Technical Lateral Buckling with Stress and Strain Analysis of Semi-slender Thin-walled Cylindrical Pinned Column Simplified with A= Ael, Jz= Jzel and Epl = Ec

The paper presents and discusses the simplified method based on the Technical Stability Theory (TSTh) of loss of stability of lateral buckling in elastic-plastic states of semi-slender columns axially compressed by a force. It is assumed that in the critical elastic-plastic transverse cross-section there are the elastic and plastic parts of the area, keeping strength. To simplify the calculations is assumed that in the elastic-plastic transverse cross-section only the elastic part of column keeps the resistance, i.e. the transverse cross-section area A= Ael, moment of inertia of a cross-section area Jz= Jzel. Also is assumed that the elastic Young’s modulus E features an elastic static moment Szel, and the plastic modulus Epl features a plastic static moment Szpl, with simplification that the plastic modulus equals the compress modulus, i.e. Epl= Ec taken from experimental researches. The graphs of functions of the curved axes, their slopes, deflections of the columns, stresses and strains in thin-walled columns and critical compressive stresses depending on the cross-section areas and slenderness ratios are presented as the theoretical examples of thin-walled cylindrical columns and compared to results obtained from experiments with columns made of steel St35.