An attempt to simulate structure and realistic images of scratches on rough polymeric surfaces

Numerical simulation of scratching has been shown to exhibit many advantages in material development and surface design and can provide detailed information associated with the scratch structure. However, the visual appearance of simulated scratches in real-world scenarios has seldom been studied. This study simulates the structure and visual appearance of scratches on rough polymer surfaces by combining the finite element method (FEM) with computer imaging (CI) techniques. FEM modeling of scratching incorporates a wide range of microgeometries in rough surfaces to ensure that the resulting scratch surfaces contain all features, regardless of whether they are visible to the human eye. Computer graphics produce realistic images of numeric scratch surfaces in real-world lighting conditions. This method demonstrates the advantages of easily simulating scratches on rough surfaces and assessing both abrasion strength and visual scratch resistance. Scratch tests on commercial polymer surfaces at different scratch forces demonstrate that the method can satisfactorily predict the structures and scales of scratches. The simulated images correlate closely with camera-acquired photographs in terms of the visual appearance of scratch surfaces, effect of lighting conditions, and dependence of the visual width of scratches on the scratching force, material, pigment, and additive in the material.