Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Blank hydroforming using granular material as a forming medium



Datum: 17.11.2014


Author


Reporter

  • Prof. Dr.-Ing. habil. M. Merklein
  • Prof. Dr.-Ing. R. Kolleck

Using granular material like small ceramic spheres for shot peening operations allows to combine benefits of warm forming of ultra-high strength steel and advantages of blank hydroforming. Additionally, this kind of forming medium shows low risks of leakage compared to gases or fluids. However, the medium itself has to be modelled for numerical process design because stress distribution inside the medium is not hydrostatic. Within the research, compression strength of single particles was investigated as a continuum model for modelling the medium in numerical simulation was build up. Together with temperature dependent flow curves and forming limit diagrams, the forming process of blanks using granular material as a forming medium was implemented in the numerical simulation and approved by comparisons with experiments. Elevated temperatures of the warm forming process as the possibility to decrease blank holder forces significantly lead to a strong increase in molding for parts made out of ultra-high strength steel grades.