Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Strategies to improve the forming results by the hydroforming of tubes and sheet pairs

Datum: 09.08.2010



  • Prof. Dr.-Ing. habil. M. Merklein
  • Prof. Dr.-Ing. R. Kolleck (TU Graz)
  • Prof. i.R. Dr.-Ing. Dr.-Ing. E.h. mult. Dr. h.c. mult. M. Geiger

The aim of this work was the development and validation of innovative process strategies by the hydroforming of tubes and sheet pairs to improve the achievable forming results. The investigations focused on the analysis of the material flow during the forming process as a key factor for the improvement of the part properties in terms of achievable bulging and thickness distribution in the critical regions of the component. First the sealing of the fluid by sheet hydroforming was analysed in order to understand the mechanism leading to the sealing of the part and determine the sealing limit in sheet hydroforming processes. The results of these investigations were used to improve the technology of hydroforming of tubes and sheet pairs in one tool. Through enhanced material flow a complex hollow part made by a tube and a sheet pair was manufactured. Further investigations focused on the development and the validation of a strategy for hydroforming double sheet parts made of inhomogeneous sheet pairs. In this strategy a counterpressure is applied to control the material flow during the process.