Approaches for load path design for stretch forming based on part surface geometry

Materials research proceedings, vol. 28, pp. 943–950

Abstract

Abstract. Stretch forming enables manufacturing large, slightly curved sheet metal parts. If the curvature is multi-directional and complex, parts often cannot be stretch-formed successfully, due to local or inhomogeneous straining that leads to early material failure, buckling or springback. To control strain distribution, the flexibility of load application needs to be improved. This can be achieved through loading at discrete points based on defined cross-sections of part geometries. However this can be applied only by multi grippers, requiring complex plant technology and control. New parameterized approaches for load path generation based on the part surface geometry for single rigid grippers have been developed to improve the flexibility of load paths. The approaches can be mainly distinguished between Surface Transformation method (ST), which transforms a surface into a curve as the base for tangential path creation and the Tool Path Fitting method (TPF). In TPF, paths are created for several cross-sections, similar to the application for multi grippers, and then compiled into one path. In this paper, the load path approaches have been applied and numerically investigated for parts with positively curved translation surfaces. Results of FE simulation of the stretch forming process show the applicability, potential and limitations of the load path design approaches.

Authors 1

1. Lisa-Marie Reitmaier corresponding Aachen Institute of Metal Forming

   RWTH Aachen University

   Affiliation as printed

   Institute of Metal Forming, RWTH Aachen University Intzestraße 10, 52072 Aachen, Germany