OJCM  Vol.7 No.3 , July 2017
Advanced Welding Technology for Highly Stressable Multi-Material Designs with Fiber-Reinforced Plastics and Metals
Abstract: Organic sheets made out of fiber-reinforced thermoplastics are able to make a crucial contribution to increase the lightweight potential of a design. They show high specific strength- and stiffness properties, good damping characteristics and recycling capabilities, while being able to show a higher energy absorption capacity than comparable metal constructions. Nowadays, multi-material designs are an established way in the automotive industry to combine the benefits of metal and fiber-reinforced plastics. Currently used technologies for the joining of organic sheets and metals in large-scale production are mechanical joining technologies and adhesive technologies. Both techniques require large overlapping areas that are not required in the design of the part. Additionally, mechanical joining is usually combined with “fiber-destroying” pre-drilling and punching processes. This will disturb the force flux at the joining location by causing unwanted fiber- and inter-fiber failure and inducing critical notch stresses. Therefore, the multi-material design with fiber-reinforced thermoplastics and metals needs optimized joining techniques that don’t interrupt the force flux, so that higher loads can be induced and the full benefit of the FRP material can be used. This article focuses on the characterization of a new joining technology, based on the Cold Metal Transfer (CMT) welding process that allows joining of organic sheets and metals in a load path optimized way, with short cycle times. This is achieved by redirecting the fibers around the joining area by the insertion of a thin metal pin. The path of the fibers will be similar to paths of fibers inside structures found in nature, e.g. a knothole inside of a tree. As a result of the bionic fiber design of the joint, high joining strengths can be achieved. The increase of the joint strength compared to blind riveting was performed and proven with stainless steel and orthotropic reinforced composites in shear-tests based on the DIN EN ISO 14273. Every specimen joined with the new CMT Pin joining technology showed a higher strength than specimens joined with one blind rivet. Specimens joined with two or three pin rows show a higher strength than specimens joined with two blind rivets.
Cite this paper: Seidlitz, H. , Fritzsche, S. , Ambrosio, M. and Kloshek, A. (2017) Advanced Welding Technology for Highly Stressable Multi-Material Designs with Fiber-Reinforced Plastics and Metals. Open Journal of Composite Materials, 7, 166-177. doi: 10.4236/ojcm.2017.73010.

[1]   Lambiase, F., Durante, M. and Di Illio, A. (2016) Fast Joining of Aluminum Sheets with Glass Fiber Reinforced Polymer (GFRP) by Mechanical Clinching. Journal of Materials Processing Technology, 236, 241-251.

[2]   Hackl, H. and Bruckner, J. (2013) Auswirkungen des Multimaterial-Leichtbaus auf die Fügetechnik. Automobil Technische Zeitschrift, 115, 808-813.

[3]   Collins, M.W. and Brebbia, C.A. (2006) Design and Nature II: Comparing Design in Nature with Science and Engineering. 6th Edition, WIT Press, Southampton.

[4]   Osiecki, T., Seidlitz, H., Gerstenberger, C., Kroll, L. and Scholz, P. (2014) Customized Metal/Composite Hybrids for Automotive Applications. Tagungsband AutoMetForm/SFU, Freiberg, 29-36.

[5]   Joesbury, A. (2015) New Approaches to Composite Metal Joining. Ph.D. Thesis, Cranfield University, Bedford.

[6]   Seidlitz, H. and Kroll, L. (2014) Hochfeste Mischbauweisenmit Thermoplastischen Faserverbunden und Metallen. Z. Joining Plastics—Fügen von Kunststoffen, 8, 106-111.

[7]   Seidlitz, H., Winter, L. and Kroll, L. (2014) New Joining Technology for Optimized Metal/Composite Assemblies. Journal of Engineering, 2014, Article ID 958501, 11.

[8]   Seidlitz, H. (2013) Entwicklung von Kraftflussgerechten Verbindungstechniken für Mischbauweisen Mitthermoplastischen Faserverbunden und Metallen. Ph.D. Thesis, Technische Universitat Chemnitz, Chemnitz.

[9]   Mattheck, C. (2013) Bauteiloptimierung nach dem Vorbild der Natur—Der Baum als Lehrmeister. VDI-Fachtagung Blasformen, Baden-Baden.

[10]   Seidlitz, H., Michailov, V. and Schleuβ, L. (2015) Verbindungstechnik für Verbundkonstruktionen aus Metall und FVK/Brandenburgische Technische Universitat Cottbus-Senftenberg. DE Patent No. 10 2015 114 511.1 (Anmeldetag: 22.10.).

[11]   Stieglbauer, W. and Kazmaier, J. (2009) Innovative, Multifunctional, Form-Locked Joining Technologyfor Dissimilar Material Combinations; Innovative, Multifunktionale, Formschlüssige Fügetechnologie für die Kombination Verschiedenartiger Werkstoffe. DVS-Berichte, 258, 100-103.

[12]   N.N. (2009) Metall mit Organischem Materialverpinnen. Fronius Press.

[13]   Jahn, J., Weeber, M., Boehner, J. and Steinhilper, R. (2016) Assessment Strategies for Composite-Metal Joining Technologies—A Review. 26th CIRP Design Conference, Stockholm, 15-17 June 2016.

[14]   Schürmann, H. (2007) Konstruieren mit Faser-Kunststoff-Verbunden. Springer-Verlag, Berlin.