Comparative studies on buckling behaviors of T joint and pipe by varying geometric parameters and analysis methods

• The effects of wall thickness and ellipticity on buckling behavior are analyzed.
• Numerical method is adopted to explore the effects of nonlinearities on buckling.
• The effects of the initial defect on the critical pressure are elucidated.
• The results show that the nonlinearities significantly reduce the critical pressure.
• There are remarkable differences on buckling between linear and nonlinear method.

In this study, buckling behaviors of T joint and pipe are comparatively investigated by varying geometric parameters and analysis methods. The effects of the wall thickness and ellipticity on buckling behavior are taken into account. According to the lowest potential energy principle, the equations of critical pressure and buckling wave number are established on the assumption of elastic buckling in the paper. However, in practice, if the structures deform largely, the T joint and pipe always experience elastic–plastic buckling, so the geometric and material nonlinearities are considered in buckling calculation. In achieving it, the finite element method (FEM) is adopted to explore the effects of those nonlinearities on buckling. Moreover, the effects of initial defect on the critical pressure are elucidated on the object of the T joint and pipe. Through rigorous FE numerical analysis, the buckling behaviors of the T joint and pipe are discussed in terms of deformation pattern, stress distribution, and critical pressure. Some interesting and useful conclusions are summarized in the paper.