Applications of analytical model for characterizing the pear-shaped tribotest for tube hydroforming. Part 2

Abstract

Applications of the analytical model for characterizing the pear-shaped tribotest are presented. Details on the derivations of the analytical model can be found in Part 1 of this paper (published in Proceedings of the Institution of Mechanical Engineers, Journal of Engineering Manufacture, 2008, Vol. 222). In this test, a tubular specimen is pressurized, forcing the material to flow towards the apex of a pear-shaped die. The height of the pear-shaped tube is a function of the magnitude of friction stress at the tube—die interface. The analytical model is used rapidly to establish the calibration curves for determination of friction coefficient in the pear-shaped tribotest. The model is also used to optimize both process and die geometric variables to suit specific tribological needs. The paper presents examples of how optimal pear-shape tribotest conditions pertaining to die geometry, tubular material properties, tube sizes, and pressure loading can be achieved via this model.