Experimentally validated finite element analysis for evaluating subsurface damage depth in glass grinding using Johnson-Holmquist model

Subsurface damages (SSD) induced during grinding of brittle materials influence mechanical and physical properties of the machined specimen. Experimental evaluation of SSD is very expensive and time consuming due to need for performing various grinding testes in one hand and post-grinding processes such as angle polishing in another hand. Meanwhile, theoretical investigation lacks accuracy due to the various simplifications involved with theoretical models. Hence, a numerical study was performed to analyze SSD in optical glass grinding using finite element method. The constitutive material behavior of glass was defined based on the Johnson-Holmquist model. Performing FEM simulations, the SSD depth was obtained for various combinations of process parameters. Based on the statistical analysis of variance, feed velocity was found to be the most significant parameter followed by depth of cut and cutting velocity. The numerical results were then compared with experimental observations using angle polishing technique and Scanning Electron Microscopy. This comparison reveals good performance of FEM in prediction of SSD depth. Finally, an empirical/ mathematical model was developed to express SSD depth as a function of process parameters. The regression model revealed that by increasing feed velocity and cutting depth, SSD depth increases, while by increasing cutting velocity, SSD depth decreases.