Effect of Micro Scale on Prediction of Thermal Residual Stresses in Multilayer Ceramic Capacitors (MLCCs)

Abstract

The conventional finite element method (FEM) cannot investigate the size effect on thermal residual stresses induced by the sintering process in micro multilayer ceramic capacitors (MLCCs). In this paper, a FE two-dimensional single layer model is developed for investigation of the effect of the micro scale on prediction of the residual thermal stresses in MLCCs. In this FE single layer model, the strain gradient effect is considered. It is found that with decreasing single layer thickness, the shear stress increases significantly in the ceramic layer near the electrode tip, which might cause cracking of the ceramic layer near the electrode tip. The numerical results also show that the predictions of the thermal residual stresses in MLCCs are strongly dependent on the micro scale. The residual thermal stresses induced by the sintering process exhibit strong size effects and, therefore, the strain gradient effect should be taken into account in the design and evaluation of MLCC devices.