A Novel Stress-Based Fracture Criterion: Theoretical and Experimental Verifications

Developing a fracture criterion that offers high accuracy while maintaining low computational cost has been a longstanding challenge among researchers. In the current study, a new modified version of the Maximum Principal Stress (MPS) criterion, named ECD-MPS, is developed. Indeed, the conventional MPS criterion is integrated by Effective Critical Distance (ECD) concept, indicating that the traditional critical distance, r c , is influenced by both material properties and the fracture modes. Additionally, a series of fracture tests is conducted on cracked disc-shaped polyurethane foam samples under Mixed-Mode I/II. The comparative results confirm the efficacy of the presented criterion and highlight the key role of the ECD concept in analyzing brittle fractures in Mixed-Modes. Moreover, it is shown that moving from pure Mode-I to Mixed-Mode I/II results in an increase in the critical distance. The validity of the proposed criterion has also been confirmed through comparison with experimental results from some available previous research.