In-situ optical approach to predict mixed mode fracture in a polymeric biomaterial

The present article promotes the usage of the digital image correlation (DIC) technique to determine the in‑situ stress and predict the onset of fracture in a cracked dental biomaterial sample. For this purpose, the elastic and fracture properties of the dental material are measured via the DIC method. To perform mixed mode fracture experiments, a modified single edge notched bend (SENB) specimen with varying crack length is introduced and utilised. From the theoretical point of view, we next implement a stress-based fracture criterion and combine it with two different critical distance models. In this regard, the in‑situ stress is formulated using the data from the DIC analysis conjugated with a supervised learning algorithm. Finally, the crack growth angle and fracture load for the tested biomaterial specimens are estimated, the comparison of which with the experimental measurements reveals good correlation.