Effects of In-Plane Geometric Shapes on Thermal Shock Resistance of Ultra-High Temperature Ceramic Components

Abstract

In thermal structural engineering, ceramic components can have various shapes and be constrained. It is traditionally known that the thermal shock resistance (TSR) of ceramic components (with conduction occurring in the thickness direction), such as disk, oval plate and rectangular plate, is independent of the in-plane geometric shapes. The present study shows that this is valid for ceramic components that are free, but when the components are constrained, the in-plane geometric shapes can have significant effects on the TSR of ceramics. Three types of components, with the edges of the lower surfaces clamped are studied. Under the second or third type thermal boundary conditions, the TSR of the disk is the best; that of the oval plate decreases as the ellipticity increases; and that of the rectangular plate is approximately equal to that of the oval plate with ellipticity of 1.2. This is because that the asymmetry of the in-plane geometric shapes, as well as the asymmetry of the mechanical boundary conditions, can worsen the TSR of the ceramics when the components are constrained. This is very important for the design and application of ceramics in the thermal structural engineering.

Keywords:

• Thermal shock resistance
• In-plane geometric shapes
• Mechanical boundary conditions
• Thermal environments
• Temperature-dependent material properties