An analytical model for the collapsing deformation of thin-walled rectangular tube in rotary draw bending

The collapsing deformation of an outer flange is the key factor affecting the forming quality of a thin-walled rectangular tube during the rotary draw bending process. Therefore, the collapsing deformation is a problem that needs an urgent solution. Firstly, based on the simplified model for loads and deformation of the outer flange, the force acted by the core die and the bending moment acted by the clamp die are obtained analytically. Then, the analytical formula of collapsing deformation is deduced based on the theory of plate and shell, and finally, the analytical model is validated by comparison with simulated and experimental results. The study is of great significance to elevate the forming quality of a thin-walled rectangular tube during the rotary draw bending process.