Estimation of Residual Thermal Stresses in a Layered Ceramic Composite

For the first time, analysis of thermal stress distribution arising in a layered ZrB₂– SiC – ZrO₂ ceramic disk during manufacturing was performed using numerical and analytical methods. The numerical modeling was implemented by the finite-element method considering the temperature dependence of properties of composite components. The residual stress distribution across the layers has a sawtooth character, in which stresses take both negative and positive values. A new analytical solution based on a simplified one-dimensional formulation of the problem for the central part of the disk was proposed. This solution shows that the residual stresses are determined not only by the thermal expansion coefficients and biaxial elastic moduli of the connected materials, but also by a thickness and location of the layers. The results of analytical solution obtained and numerical modeling were in a good agreement. It is shown that, for estimating the residual stress in a laminated composite with assumption that the properties of composite components are temperature-independent, it is appropriate to apply the thermomechanical characteristics corresponding to a high temperature rather than a room or average ones. The porosity effect on the residual stresses in a ceramic laminate was studied. It is found that the consideration of porosity decreased the residual stresses only in the layers where it was entered. Results of the study provide a basis for analyzing residual stresses in the laminates of different compositions and in specific engineering applications.