Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Failure analysis of material superimposed with process caused tensions and alternating bending loads

Project Status: finished


The objective of EFB 08/114 research project is to improve the failure prediction for sheet metal which was already prestressed using drawbeads. The use of drawbeads finally leads to a superimposition of tension and alternating bending stresses in the material. Especially small and medium sized companies are challenged by the economical need for shorter product creation cycles and the variety of sheet metal products. Demanding a reduction of a car’s overall mass at the moment, the design of the body in white gets even more important.

To sustain the quality of sheet metal manufacturing processes, finite element analysis showed to be a reliable and successful tool. Doing a design and analysis accurate, cheap and in a short amount of time still is very difficult. That’s also because of the very complex material models and its implementation.

Special parts and areas which were overlaid with a superimposition of tension and alternating bending show big differences between simulation and experimental results. The use of a drawbead obviously leads to prestressed material what can influence the sheet metal’s behavior in the succeeding process. That causes incorrect failure analysis and inappropriate and wrong predictions for the whole system.

During this project, different drawbead geometries will be used to preload different sheet metal materials and define experimental the real point of failure. Afterwards, the material will be fully characterized and compared to unloaded material to finally improve the simulation.

Scheme of rectangular cup drawing with drawbead (left) and change of failure limit by using a drawbead (right)

Scheme of rectangular cup drawing with drawbead (left) and change of failure limit by using drawbead (right)

Research Groups



    • Schmid, H.; Suttner, S.; Merklein, M.:
      An incremental analysis of a deep drawing steel’s material behaviour undergoing the predeformation using drawbeads.
      In: 36th IDDRG Conference – Materials Modelling and Testing for Sheet Metal Forming (Edtrs.): IOP Conf. Series: Journal of Physics: Conf. Series 896 (2017) 011001 , https://doi.org/10.1088/1742-6596/896/1/011001, 2017, published

    • Schmid, H.; Suttner, S.; Merklein, M.:
      Investigation of process induced changes of material behaviour using a drawbead in forming operations.
      In: R. H. Schmitt, G. Schuh (Edtr.): 7. WGP-Jahreskongress Aachen, 5.-6. Oktober 2017, Apprimus, 2017, pp. 37-42

    Letztes Update: 22.08.2016