Abstract
The experimental technique for the investigation of thermal shock fracture of ceramics under various stress ratios was developed. In order to determine the testing configurations, the thermal stress field in specimen was analyzed using FEM. It was found that the ellipse specimen and cooling rod with the specific aspect ratios yield the designated stress ratio which is constant during the test. The corresponding experiments were also carried out. The specimen was heated to 650 ℃ and quenched by means of contacting with a cool copper rod. The transient temperature on the ellipse specimen was measured by IR camera and the thermal stress was calculated by FEM. During thermal shocked fracture AE signals were detected by an AE sensor attached on the bottom of the copper rod. The constant thermal stress ratio was obtained corresponding to the result of FEM calculation. Consequently, the testing configuration, which enables the evaluation of thermal shock fracture behavior under various stress ratio, was developed.
