Characterizing the Frictional Interface in Friction Stir Welding Characterizing the Frictional Interface in Friction Stir Welding
the other mode, plastic shear deformation friction, has frictional force independent of normal force. A linear statistical model has been developed to characterize each of the frictional modes for the polycrystalline cubic boron nitride (PCBN) tool and 1018 steel work piece interface as functions of temperature, velocity, and normal force. Two linear models were chosen. A statistical method called membership function regression was used to determine the coefficients of these two models. The resulting model has a correlation of (Predicted Force) = 1.0445(Measured Force) with an R^2 value of 0.83.
The second method was an attempt to measure friction with a measurable contact area at a range of temperatures, velocities, and normal pressures. This method rubs the end of a cylindrical rod with a concentric cylindrical pocket against a flat plate. This method caused precessions of the tool on the workpiece. As a result of this precession, plastic shear deformation friction measurements are invalid. However, Coulomb-Amonton's friction is still valid. The experiments of the PCBN-stainless steel interface found that Coulomb-Amonton's friction did not depend on temperature and velocity. In addition, no plastic shear deformation friction was identified using this method and this interface combination.
School:Brigham Young University
School Location:USA - Utah
Source Type:Master's Thesis
Keywords:friction stir welding pcbn deformation membership function regression stainless steel
Date of Publication:03/09/2007