Crack Tip Position Determination Using Infrared Thermography and Digital Image Correlation

This paper presents an experimental and numerical study of the crack initiation and propagation in the nodular cast iron grade EN-GJS-400-18-LT. Therein, non-contact Digital Image Correlation is used to study the development of the tensile damage along the crack path and to identify the crack tip position. Based on the experimental results, a new three-dimensional constitutive model is proposed to simulate the low-cycle fatigue behaviour of considered material. Within the framework of numerical investigations the cyclic plasticity model together with the damage initiation and evolution criteria are applied to study the fatigue damage in the compact tension specimen near the notch and the crack tip. The computational procedure accuracy is verified by comparing the computed results with the real experimental data. After successful application of the digital image correlation technique to identify the crack tip position, the next step is to investigate the development of the dissipated energy along the crack path using the infrared thermography.