The calculation and influencing factors analysis of stress neutral layer displacement in tube bending

To study the displacement and influencing factors of the stress neutral layer in tube bending, the stress-strain discipline is analyzed based on the plastic theory. Then the approximate formula of the stress neutral layer displacement is deduced with the consideration of the wall thickness variation and the material hardening characteristics. Finally, to discover the sensitivity factors of the stress neutral layer displacement, the orthogonal design method is introduced. It is considered that the relative bending radius and the hardening exponent has significant effects on stress neutral layer displacement, while the other parameters are not obvious. The comparison of theoretical calculations and numerical simulation results prove the correctness and validity of the theoretical analysis.