Title: Effects of viscous dissipation in flow-influenced tube hydroforming

Authors: P. Dal Bo, M. Geiger

Addresses: Chair of Manufacturing Technology, University of Erlangen-Nuremberg, Egerlandstr. 11, D-91058 Erlangen, Germany. ' Chair of Manufacturing Technology, University of Erlangen-Nuremberg, Egerlandstr. 11, D-91058 Erlangen, Germany

Abstract: In tube hydroforming, the forming results can usually be improved if axial feeding at one or both tube ends is enabled. For very long parts, however, owing to the high-friction forces acting between the tube and die at high pressure, no material flow to the forming area occurs. With the flow of a highly viscous fluid on the tube|s surfaces, external pressure and tangential axial forces are generated, which reduce the normal contact force between the tube and die and help the sliding of the tube in the forming zone. In this paper, the behaviour of a flowing Newtonian highly viscous fluid was analysed. 2D and 3D coupled thermomechanical FE analyses were done to study the effects of viscous dissipation and conductive and convective heat transfers between fluid and tool. The results of the simulation were validated with temperature measurements during the experiments on the hydroforming tool.

Keywords: tube hydroforming; viscous dissipation; coupled FEA; finite element analysis; modelling; highly viscous fluids; fluid flow; thermomechanics; conductive heat transfer; convective heat transfer; simulation.

DOI: 10.1504/IJMMP.2008.016947

International Journal of Microstructure and Materials Properties, 2008 Vol.3 No.1, pp.100 - 112

Available online: 31 Jan 2008 *

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