Analysis of residual stresses in engineering ceramics during electrical discharge grinding

Abstract

The non-uniform high temperature distribution of engineering ceramics generated during electrical discharge grinding results in residual stresses. These residual stresses can decrease the engineering ceramics in fatigue life and strength, even lead to micro-cracks. A finite element-based analysis of residual stresses in engineering ceramics electrical discharge grinding is presented. The temperature distribution of the ceramics during the machining has to be analyzed first by finite element method (FEM) for non-linear transient temperature field. Two different heat sources have to be developed due to the dissimilarity between the grinding heat source and the EDM heat source. The temperature distribution within ceramics due to grinding is determined by moving heat source. Gaussian heat distribution has been considered in the calculation of temperature distribution due to EDM. Temperature distribution in the ceramics due to electrical discharge grinding is obtained by using superposition. Then the residual stresses in the ceramics are determined by FEM for the thermal elastic-plasticity using the temperature distribution of electrical discharge grinding. The distribution of the temperature fields and residual stresses is analyzed. The analysis of residual stresses can predict the micro-cracks.