Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Fundamental investigation on the influence of part shape and material properties in sheet hydroforming



Datum: 07.06.2004


Author


Reporter

  • Prof. Dr.-Ing. Dr.-Ing. E.h. mult. Dr.h.c. M. Geiger
  • Prof. Dr.-Ing. M. Kleiner, Universität Dortmund

Sheet metal hydroforming is an innovative forming technology for the manufacturing of complex hollow bodies with optimal strength to weight ratio. This work presents several theories, methods and techniques which help to understand the essential relationships between part shape, material properties and forming results, based on analytical models, finite element analysis and laboratory trials. In particular the hereby defined hydroforming shape factors for the free and constrained bulging (HSF1 and HSF2), the hydroforming material factor (HMF) and the analytical model of the constrained bulging in the edge areas represent some effective and useful methods for the designer and process engineer. They enable the definition of guidelines for ?design for hydroforming?, the choice of an appropriate material combination in double sheet hydroforming and the prediction of the process parameters during the hydroforming operation. Additionally, this work presents several practical suggestions and recommendations for a correct part and process design, as well as some technical solutions for improving the process robustness and the final forming results. In particular the use of a sealing medium in suspension in the hydroforming fluid constitutes an innovative and effective sealing technology for the double sheet hydroforming process. Using the developed sealing medium better forming results could be achieved while the robustness of the process could be improved.