Fracture Mechanics Analysis of Thermal Shock Cracking of Ceramics in Laser Heating

Abstract

The purpose of this study is to establish the evaluation method for thermal stress fracture reliability of ceramic components by means of laser heating. To elucidate the thermal shock cracking induced by laser heating, the stress distribution and the thermal stress intensity factor are first analyzed using finite element method, then laser thermal shock experiments are conducted on partially stabilized zirconia. It is found in the analysis that the minimum principal stress direction is radial near the surface outside the beam radius, and the maximum value in the thermal stress intensity factor appears at the position of 1.5-1.8 times outside by the beam radius. The thermal stress intensity factor monotonously increases in heating process, while it decreases in cooling process. The thermal stress intensity factor also tends to decrease after a certain peak value with increase in the crack length. The crack is observed to form and grow in the radial direction and it is also observed to arrest after a certain growth. The observed behavior of thermal shock cracking is coincided with analytical results.