Interaction between Euler Buckling and Brazier Instability*

The interaction between Euler buckling and Brazier instability in an orthotropic cylindrical tube was investigated. A simple closed-form interaction curve was obtained by using the principle of minimum potential energy including the 3D extended Brazier’s 2D type cross-section ovalization and the potential energy of axial compression. The interaction curve consists of an Euler buckling load and a bending instability load, which slightly differs from Brazier’s bending instability load. Hence, the differences between these bending instability loads were also investigated. The interaction curve was validated by comparing it with the finite element analysis results from the open literature, and it was confirmed that it gives good estimates.