Laser Spot Thermography of Ceramic Materials

Abstract

The paper presents an application of laser spot thermography for damage detection in ceramic materials. The measurement technique is based on an external heat delivery to a test sample by means of a laser pulse and signal acquisition by an infrared camera. Damage detection is based on the analysis of surface temperature distribution near the exciting laser spot. The technique is nondestructive, noncontact and allows for full-field measurements. This paper presents an application of laser spot thermography to a ceramic sample with surface breaking crack. This type of damage is very common in case of ceramic materials as it often arises due to the manufacturing process or during the service period. This paper briefly discusses theoretical background of laser spot thermography, describes the experimental test rig and signal processing methods involved. Damage detection results obtained with laser spot thermography are compared with reference measurements obtained with vibrothermography. This is a different modality of active thermography, that have been previously proven effective for this type of damage. We demonstrate that both measurement techniques can be effectively used for damage detection and quality control applications of ceramic materials.