Forming mechanism of extrusion self bending of aluminum alloy sheet profile and optimum design of die

Based on the theory of continuum mechanics, the relationship between the exit velocity distribution and the radius of curvature of the plate during the ideal self-bending process is obtained. A new process for the self-bending extrusion of aluminum alloy plates was proposed. By designing the structure of special-shaped guide cavity, the uneven flow of metal in the die cavity was produced, so the bent profile is directly extruded. By using numerical simulation, the self bending deformation mechanism, metal flow characteristics and distribution of residual strain in the process of sheet profile extrusion were analyzed. The response surface prediction model of each variable to the radius of curvature of extrusion self bending was established by using the Latin hypercube sampling method and the finite volume method. Under the condition of a specified bending radius of 1900 mm, an objective function optimization model with a penalty function was established. The algorithm obtains the optimal cavity structure and process parameters, and conducts trial experiments. The experimental results show that the self-bending sheet extrusion is stable, the measured radius of curvature is 2071 mm, the grain size inside and outside of the curved sheet is uniform. © 2021, China Science Publishing & Media Ltd. All right reserved.