Analytic Prediction of the Process Parameters for Form-Fit Joining by Die-Less Hydroforming

Abstract:

The Commission of the European Communities aims for a reduction of new car CO2 emissions of 120 grams per kilometer in 2012. As a result of the omnipresent efforts of the automotive industry to hit these tighter emission standards innovative lightweight strategies, e.g. the use of lightweight materials are developed. This entails new joining techniques that are appropriated to the new lightweight materials. The die-less hydroforming process is a joining method for tubular joints which meets the new demands of lightweight strategies. Since there is no need for any additional connection elements or filling material, it is an interesting alternative to conventional welding and riveting processes. The present paper describes the basic principle of the die-less hydroforming joining technology with a special focus on form-fit connections. An analytical model, based on the membrane theory with an additional local consideration of bending stresses is developed. This analytic approach can be used to calculate the working fluid pressure, required to bulge the tube material into the groove of the outer joining partner. Taking into account the material parameters as well as the groove and tube geometry, this model allows a reliable process design. Additionally, validation of the model by experimental investigations will be provided.

• Periodical: Key Engineering Materials (Volumes 504-506)
• Pages: 393-398
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.504-506.393
• Online since: February 2012
• Authors: Soeren Gies, Christian Weddeling, Michael Marré, Lukas Kwiatkowski, A. Erman Tekkaya
• Keywords: Die-Less Hydroforming, Form Fit Joints, Joining by Forming, Lightweight Frame Structures

References

[1] B. Frenzel, P. Kurzweil, H. Rönnebeck, Electromobility concept for racing cars based on lithium-ion batteries and supercapacitors, Journal of Power Sources 196 (2011) 5364-5376

DOI: 10.1016/j.jpowsour.2010.10.057

[2] A. Piller, H. E. Friedrich, G. Kopp, F. Henning, Fügen von faserverstärkten Kunststoffen in Multi-Material-Fahrzeugstrukturen - aktuelle Forschungsergebnisse, in: Manual of the 11th international AVK conference, 22.–23. September 2008, Essen, Germany.

[3] M. Marré, Grundlagen der Prozessgestaltung für das Fügen durch Weiten mit Innenhochdruck, PhD Thesis, Shaker Verlag, Aachen, 2009, ISBN: 978-3-8322-8361-2.

[4] S. Yokell, A working guide to shell-and-tube heat exchangers, McGraw-Hill, New York, USA, 1990, ISBN: 0-07-072281-1.

[5] H. Krips, M. Podhorsky, Hydraulisches Aufweiten – ein neues Verfahren zur Befestigung von Rohren, VGB Kraftwerkstechnik 56 (1976), 456-464.

[6] W. Przybylski, J. Wojciechowski, M. Marré, J. Rautenberg, M. Schikorra, Influence of the interface modifications on an increase of strength of aluminium tubular joints produced by hydroforming, 2007.

[7] M. Garzke, Auslegung innenhochdruckgefügter Pressverbindungen unter Drehmomentbelastung, PhD Thesis, Fortschritt-Berichte VDI, 350, VDI Verlag, Düsseldorf, (2001)

[8] C. Weddeling, S. Woodward, M. Marré, J. Nellesen, V. Psyk, A. E. Tekkaya, W. Tillmann, Influence of groove characteristics on the strength of form-fit joints, Journal of Materials Processing Technologies, 211 (2011), 925-935

DOI: 10.1016/j.jmatprotec.2010.08.004

[9] Z. Marciniak, J. L. Duncan, Mechanics of Sheet Metal Forming, Butterworth Heinemann, Oxford, 2002, ISBN: 0-7506-5300-0.

[10] W. Beitz, K.-H. Grote, Dubbel – Taschenbuch für den Maschinenbau, 19. Edition. Springer-Verlag, Berlin, Heidelberg, 1997.

[11] K. Lange, Umformtechnik – Handbuch für Industrie und Wissenschaft, Volume 3: Blechbearbeitung, Springer-Verlag, Berlin, Heidelberg, 1990, ISBN: 3-540-50039-1.

[12] Y.-M. Hwang, Y.-K. Lin, T. Altan, Evaluation of tubular materials by a hydraulic bulge test, International Journal of Machine Tools and Manufacture, 47 (2007), 343-351.

DOI: 10.1016/j.ijmachtools.2006.03.009