Multi-point incremental bending of high strength steel plate with doubly curved surface under minimum strain energy loading path

Abstract

Abstract High strength steel plates with doubly curved surface in small batch have been widely applied in shipbuilding, aerospace, automobile and other manufacturing fields to meet the lightweight market demand. To achieve the doubly curved high strength steel plates with smaller forming force, the multi-point incremental bending process was proposed. In addition, to deform the high strength steel Q345B plates efficiently and accurately, the tools’ loading path strategy under the minimum strain energy field (that is, along the principle curvature direction) with considering the springback height was proposed. In this paper, the influence of single point bending-springback characterization at different bending positions and that with different incremental bending depths are analyzed based on experiments and numerical simulations to finally determine the whole springback height distribution for the entire high strength steel plate. Then the high strength steel plate with target doubly curved surface was deformed experimentally by the multi-point incremental bending experiments based on two kinds of tools’ loading paths according to whether considers the springback height of the high strength steel plate. The maximum loading forces and the absolute shape error were compared and analyzed. Results validated the reliability of the multi-point incremental bending experiment along the principle curvature direction with considering the springback height and the paper also puts forward the following up to be improved for the flexible incremental bending process in the future.