Analytical model for friction coefficient determination in hydroforming of thin-walled tube elements

Abstract

Industrial branches where the changes occur with the introduction of the new technologies in a very short period are automobile and aviation industries, because the securing and ergonomic criteria had to be achieved. These demands initialized setting of the new productive philosophy, which is based on a modern production like plastic forming and modelling with an incompressible fluid. A tube hydroforming got a significant role in the last five years and is considered as a technology of rapid development. This paper provides researches and analyses of hydroforming of thin-walled tube elements. A workpiece and die contact for hydroforming in a work process manifests with the friction force which has an influence on: axial force, axial punch feed and workpiece wall thickness. The stress-strain state and their disposition during the tube hydroforming are foundation where the friction influence in tube hydroforming is based on. It provides an analysis of deformation zones and friction in T shape tube hydroforming. An analytical model of friction coefficient change in hydroforming between a tube and die has been carried out. The main objective of this paper is to suggest new analytical model for friction coefficient determination in hydroforming of thin-walled tube elements which describes process the most realistically. This paper provides an experimental way of needle sensor setting in measuring of the contact friction in T shape tube hydroforming.