Minimization of Surface Friction Effect on Scratch-Induced Deformation in Polymers

Surface friction plays an important role in influencing the stress field development during scratch process, thus, scratch-induced deformation mechanisms. In this study, three-dimensional finite element method (FEM) parametric study was performed along with experimental validation to investigate the effect of surface friction on scratch-induced deformation and its correlation with the constitutive behavior of polymers. As scratch depth and shoulder height are the key parameters for causing scratch visibility, the focus is to investigate the effect of surface friction on these two scratch-induced deformation features and how the surface friction effect can be altered by varying the constitutive parameters. The FEM findings and experimental observations indicate that onset of groove formation during the scratch process is strongly influenced by yield stress and coefficient of surface friction. Also, the relative frictional effect on scratch-induced deformation becomes minimal if the post-yielding strain hardening slope of the polymer is high. (C) 2012 Society of Plastics Engineers