Thermal Stress Analysis in Ceramic Disk Subjected to Thermal Quenching

Abstract

For evaluation of thermal shock resistance of ceramics by the quenching method, it is important to estimate the thermal stress distribution and history in the specimen. Thermal stress under quenching can not be measured directly in the experiment. Therefore, the temperature distribution generated by quenching was numerically calculated and the transient thermal stress distribution was estimated for the ceramic disk. The calculated maximum thermal stress and the time required were proposed as the correlative equations, respectively. The former equation of maximum thermal stress is useful to evaluate the thermal shock resistance of ceramics. The fracture time can be estimated by the latter equation of the time at the maximum thermal stress. If the experimental fracture time agrees with the calculated one, it is considered that the fracture occurs only by the thermal stress. Furthermore, these equations were compared with those of slab specimens to discuss the differences in thermal stress history and distribution. The effects of temperature dependence of thermal constants on thermal shock resistance have been evaluated. The strain energy accumulated in the disk during the fracture process was also calculated by the tensile thermal stress at the surface.