A strain-based criterion for predicting size-dependent fracture resistance of quasi-brittle materials under mixed mode loading

• Published in: Engineering fracture mechanics 2024-11, Vol.310, p.110513, Article 110513
• Main Authors: Aghabeigi, Mahya, Akbardoost, Javad, Reza Ayatollahi, Majid
• Format: Article
• Language: English
• Subjects: Mixed-mode loading condition; Modified maximum tangential strain criterion, Fracture resistance; Quasi-brittle materials; Size effect
• ISSN: 0013-7944
• DOI: 10.1016/j.engfracmech.2024.110513

•A strain-based criterion (MMTSN) is suggested for size effects on fracture in quasi-brittle materials.•MMTSN utilizes only singular and first non-singular terms of Williams series expansion.•A new formulation is suggested for calculating the critical distance from the crack tip.•The MMTSN criterion is evaluated by the experimental data available in the literature.•Good consistency is found between the experimental results and theoretical predictions. In the present study, a strain-based approach called the modified maximum tangential strain criterion has been developed for evaluating size effect on the mixed-mode fracture resistance of quasi-brittle materials. This approach relies on the generalized maximum tangential strain criterion, which considers the singular (K) and the first non-singular (T) terms of Williams series expansion. Furthermore, as an important and size-dependent parameter in the proposed criterion, a new formulation is presented to calculate the critical distance (rc). The predictions of the new criterion are compared not only with the available experimental data, but also with the results estimated by another size effect criterion named the modified maximum tangential stress criterion. It is shown that the proposed strain-based criterion is highly capable of estimating the size-dependent mixed-mode fracture behavior of quasi-brittle materials without requiring to compute the other higher order terms.