Brittle failure of key-hole notches under mixed mode I/II loading with negative mode I contributions

• Published in: Engineering fracture mechanics 2016-12, Vol.168, p.51-72
• Main Authors: Torabi, A.R., Majidi, H.R., Ayatollahi, M.R.
• Format: Article
• Language: English
• Subjects: Brittle fracture; Brittleness; Criteria; Experiments; Failure; Fracture mechanics; GPPS; Key-hole notch; Mixed mode I/II loading; Negative mode I contribution; Notches; Polystyrene; Polystyrene resins; Stresses
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2016.10.007

•Mixed mode failure is studied in key-hole notches under negative mode I conditions.•Experiments are conducted on Key-BD GPPS specimens for various notch tip radii.•Failure load and initiation angle are predicted using Key-MTS and Key-MS criteria.•Two groups of critical distances are utilized in the theoretical predictions.•Both criteria could predict the experimental fracture loads well. Brittle failure of key-hole notches is investigated experimentally and theoretically under mixed mode I/II loading with negative mode I contributions. The key-hole notched Brazilian disk specimen made of the general-purpose Polystyrene is utilized for conducting the fracture experiments. To predict the experimental results, the key-hole notch maximum tangential stress and key-hole notch mean stress criteria are utilized. It is shown that both criteria could provide good predictions to the experimental results of the fracture load. Moreover, the key-hole notch mean stress criterion with the experimentally determined critical distance is shown to be the most accurate failure criterion.