Technical Lateral Buckling with Stress and Strain Analysis of Semi-slender Thin-walled Cylindrical Pinned Column made of Steel St35 Simplified with A= Ael, Jz= Jzel, E= Ec , Epl = Esc

The paper continues and discusses the next case of the simplified method of 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 again assumed that in the critical elastic-plastic transverse cross-section there are the elastic and plastic parts of the area, keeping strength. It is still 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 as well as still is assumed that the elastic Young’s modulus E features the elastic static moment Szel, and the plastic modulus Epl features the plastic static moment Szpl. The new simplification is that the elastic Young’s modulus E is varying with the slenderness ratio Lambda and equals the compress modulus, i.e. E= Ec(Lambda) as well as the plastic modulus equals the secant compress modulus also is varying with the slenderness ratio Lambda, i.e. Epl= Esc(Lambda) taken from the experimental researches. The graphs of the functions of the curved axes, their slopes, deflections, stresses and strains of the thin-walled cylindrical column D45x1x545 mm with slenderness ratio Lambda= 35 as well as the critical compressive stresses depending on the cross-section areas A and slenderness ratios Lambda are presented as the theoretical examples with the new assumptions and compared to results obtained from experiments with thin-walled cylindrical columns made of steel St35.