Deep Drawing of One-Sided, Stiffness Increasing Sheet Metal Composites

Abstract:

Hybrid sheet metal composites do show advantages compared to monolithic materials when strength, stiffness, and damping characteristics are set to a global optimum. Even though the mechanical properties of hybrid sheet metal composites have been improved in recent years, the application of such hybrid materials in the automotive industry is not well-established due to insufficient knowledge about their forming characteristics (e.g. in deep drawing process). Stiffness increasing composites consist of two metal sheets and a viscoelastic damping layer in-between: the outer sheet reveals stamped beads which increases stiffness of composite while the inner sheet serves as cover sheet. This paper deals with challenges of formability of stiffness increasing composites in industrial deep-drawing processes. The main concern is dimensional stability and accuracy of those layered materials after finishing the forming process. In order to ensure accuracy of formed parts, a methodology was developed for increased quality of sheet metal composites. Depending on the drawing limit ratios and blankholder forces, which evaluate the drawability of component in general, the drawing limit ratio is influenced for profound or insufficient residual bead heights and widths. Besides insufficient bead height, which causes a reduction in moment of inertia, inner marks on the visible outer sheet hamper a broad application in practical use. Finally, paper provides detailed recipies for manufacturing and tool layout for deep drawing objectives of such composite material.

• Periodical: Key Engineering Materials (Volume 716)
• Pages: 879-890
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.716.879
• Online since: October 2016
• Authors: Dennis Hofmann*, Mathias Liewald
• Keywords: Deep Drawing, Sandwich, Sheet Metal Composites, Stiffness Increase

References

[1] Information on http: /www. global-automotive-lightweight-materials-detroit-2014. com/ (Applying advances in lightweight materials to multi-material mass produced vehicles. Automotive Lightweight Materials, Detroit, 2014).

[2] H.P. Degischer, S. Lüftl, Leichtbau, first edition, Wiley Verlag, (2009).

[3] D. Hofmann, M. Liewald, Material characterization and properties of newly developed sheet metal composites with stiffness increasing layers. Proceedings of IDDRG 2015, (2015).

[4] C. Bolay, Beitrag zur Umformung von ebenen und versteiften Schichtverbundwerkstoffen. Dissertation, University of Stuttgart, (2014).

[5] M. Nutzmann, Umformung von Mehrschichtverbundblechen für Leichtbauteile im Fahrzeugbau. Dissertation, University of RWTH Aachen, (2008).

[6] J. Buhl, Umformverhalten und Grenzen von Schichtverbundwerkstoffen. Dissertation, University of Siegen, (2014).

[7] M. Milch, Tiefziehen von geklebten Doppellagenblechen. Dissertation, University of Hannover, (2007).

[8] O. Sokolova, Deep drawing properties of lightweight steel/polymer/steel sandwich composites. Archives of Civil and Mechanical Engineering. 12 (2012) 105–112.

DOI: 10.1016/j.acme.2012.05.001

[9] K.F. Karlsson, A. Aström, Manufacturing and applications of structural sandwich components. Royal Institute of Technology, Sweden (1998), p.100.

[10] B. Klein, Leichtbau-Konstruktion, Berechnungsgrundlagen und Gestaltung, GWV Fachverlage GmbH, Wiesbaden, (2007).

[11] F.G. Rammerstorfer, K. Dorninger, A. Starlinger, Composite and Sandwich Shells, In: Nonlinear Analysis of Shells by Finite Elements, Springer, Wien, New York, (1992).

DOI: 10.1007/978-3-7091-2604-2_6

[12] J. Wiedemann, Leichtbau, 2nd edition, Springer, Berlin, Heidelberg, New York, (1996).

[13] G. Lang, Biegeverhalten von Kernverbund-Systemen, J. Appl. Polym. Sci. 22 (1978) 2831-2856.

[14] F. Burbulla, Kontinuumsmechanische und bruchmechanische Modelle für Werkstoff-verbunde. Dissertation. University of Kassel, (2015).

[15] G. Reyes, H. Kang, Mechanical behavior of lightweight thermoplastic fiber-metal laminates. J. Mater. Process. Tech. 186 (2007) 284-290.

DOI: 10.1016/j.jmatprotec.2006.12.050

[16] O. Sokolova, A. Carrado, H. Palkowski, Metal-polymer-metal sandwiches with local metal reinforcements: a study on formability by deep drawing and bending. Compos. Struct. 94 (2011) 1-7.

DOI: 10.1016/j.compstruct.2011.08.013

[17] H. Palkowski, O. Sokolova, A. Carrado, Forming potential of steel/polymer/steel sandwich composites with local plate inserts. Material Science Forum, 706-709 (2012), pp.681-686.

DOI: 10.4028/www.scientific.net/msf.706-709.681

[18] O. Sokolova, A. Carrado, H. Palkowski, Adhesion and formability of thin steel/polymer/steel hybrid sandwich composites, In: Hirt G, et al., editors. I International conference on technology of plasticity, ICTP 2011. Aachen, Germany; (2011).

[19] G. Lange, Beitrag zum Umformverhalten von dreischichtigen austenitischen Sandwich-verbunden mit polymerer Kernschicht, Institut für Metallurgie, Dissertation, TU Clausthal, (2005).

[20] M. Liewald, P. Schmid, Entwicklung einer Rückfederungskompensationsstrategie. wt-online, Issue 10/2014, pp.649-653.

DOI: 10.37544/1436-4980-2014-10-649