Effect of constitutive behavior on scratch visibility resistance of polymers—A finite element method parametric study

Three-dimensional finite element method (FEM) parametric study was performed by simulating linearly progressive load scratch process on a polymer substrate with a spherical-tip indenter, following the established ASTM D7027-05 and ISO 19252:08 testing protocol. The scratch depth and shoulder height of the groove formed during scratch, which has been shown to be directly related to the scratch visibility resistance of polymers, is simulated by varying a set of material constitutive parameters, namely, yield stress, strain softening slope, strain hardening slope, strain at stress recovery, and strain before hardening. The simulation results indicate that yield stress and strain at stress recovery are two most important parameters that affect scratch depth and shoulder height, thus scratch visibility resistance, of a polymer. Implication of the present findings for designing scratch resistant polymers is discussed.