Numerical Analysis of Heat Transfer Process in Pulsed Thermography Detection on Electrical Ceramic Materials

Pulsed thermography has promising applications in nondestructive testing of electrical equipment made of ceramic materials. In this method, an external source of energy is required to induce a temperature distribution difference between defective and nondefective areas in the specimen under examination. There is a definite correspondence between the internal structural information of the specimen and the change of its surface temperature distribution. Therefore, it is necessary to have a sufficient understanding of the heat transfer mechanism of electrical ceramic materials in order to design the detection system more effectively, and to establish an accurate functional relationship between the surface temperature change and the internal structural information of the material. Defects identification methods of pulsed thermography for nondestructive testing of electrical ceramics and influences of thermal excitation to detection results were studied in this manuscript. The quantitative relationships between surface temperature distribution and its influencing factors, such as amplitude and pulse width of thermal excitation and defect size and depth, were researched, which laid the theoretical foundation of quantitative analysis of defects and method improvement.