Modeling The Effects Of Ceramic Mesocopic Structure On Stress Distribution By Finite Element Method

Ceramic, due to having many excellent properties comparing with other generalmaterials, has caused many countries attention in the word, but its brittleness haslimited its application. The properties of ceramic are not only affected by itsingredients, primary crystal and msoscopic structures, but also mainly depend on itsprimary crystal and mesoscopic structures once it ingredients are determined. So it isof significance to analysis the mesoscopic structures of ceramic. Observation themesoscopic structures of ceramic and its effects of the stress distribution atmesoscopic levels is limited by many conditions. The development of computer andfinite element method, proffer a new way for this research.In this paper, the FEM-models of the mesoscopic structures of cordierite ceramicestablished on the basis of the cordierite-mesoscopic pictures, which are obtained bySEM (scanning electronic microscope). The effects of grain-boundary, grain-shapeand pore to the mesoscopic stress distribution have been analyzed. The result showsthat the max-stress increases with the difference between grain and grain-boundary atthe same boundary conditions and the max-stress appears at the boundary between thegrains which shapes are more irregular. The stress distributions of the model becameeven while the differences of the properties between grain and grain-boundary reduce.Great stress exits around the pores, and this will become the origin of the mesoscopiclevel crack. Thermal stress appears during the process from high temperature to roomtemperature, due to miss orientation and anisotropy thermal conductivity of grains,which can also cause mesoscopic crack and decrease toughness of the ceramic. Butthe thermal stress can be relaxed partly by the glass, which appears asgrain-boundaries in ceramic.