Method for Damage Assessment of Ceramics after an Impact

An image-processing method for damage assessment of ceramics after an impact is presented in this article. The method is based on the analysis of digital gray-scale images of the damaged surfaces and consists of successive steps of image enhancement, including normalization of light intensity, rotation of the light intensity space, histogram equalization, thresholding, and determination of the parameter characterizing the density of image distortions. The method allows the use of digital images taken under imperfect lighting conditions. The method was applied for damage assessment of AD995 ceramic specimens. The specimens were subjected to a double pulse loading generated with the help of the split Hopkinson pressure bar. As evident from the analysis of experiments, the parameter density of surface image distortions correlates strongly with the amplitude of the incident strain pulse as well as with the descriptive characteristics of the deformed shape of the specimen.