A study on springback of profile plane stretch–bending in the loading method of pretension and moment

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• The profile with any cross-section was taken as the study object.
• The mechanical models of profile stretch-bending were established.
• Different distribution states of stress and strain on cross-section were described.
• The analytic method for springback of profile plane stretch-bending was obtained.
• The research on two typical profiles was performed to verify the analytic method.

The springback law and springback prediction are always the difficulties in the field of profile stretch–bending processing. Because of the urgent demand for stretch–bending flexible manufacturing, the study on stretch–bending springback aiming at the profile with a given cross-section cannot meet the requirement. In this paper, the profile with any cross-section was taken as the study object. In the loading method of pretension and moment, the mechanical models of profile stretch–bending were established based on the classical elastic–plastic theory and the characteristic of strain superposition. Different distribution states of stress and strain on cross-section were discussed, and the method of discriminating different distribution states was given. The universal analytic method of solving the plane stretch–bending springback of profile with any cross-section was obtained. Two kinds of typical profiles with U-section and rectangular section were taken as examples to verify the theoretical analysis. The stretch–bending springback laws obtained by theoretical analysis, numerical research and experimental research agreed well. This study provides a theoretical foundation for stretch–bending flexible manufacturing and has certain theoretical and engineering guidance value.