Strain-based criteria for brittle failure prediction of solids containing blunt V-notches under pure mode I loading

Abstract

This study introduces two novel failure criteria developed for the first time to predict the mode I brittle fracture behavior in components weakened by blunt V-notches. These criteria, named the Mean Strain (MST) and Point Strain (PST), rely on mean and point tangential strain components near the blunt V-notch border, respectively. The foundation of strain-based criteria has previously been used to predict brittle fracture in cracked samples under mixed-mode I/II and I/III loading conditions. Here, we investigate its applicability in predicting the fracture behavior of components weakened by blunt V-notches under pure mode I loading. To evaluate their accuracy, the proposed criteria undergo initial validation using available mode I blunt V-notch fracture experiment data across various materials like PMMA, graphite, and rock. Additionally, a series of fracture tests are conducted on brittle epoxy resin samples in rectangular plate forms weakened by blunt V-notches with varying notch opening angles and radii. The results exhibit good agreement between the outcomes using the developed strain-based criteria and the test results, particularly for specimens with larger notch tip radii. Notably, in certain materials, such as rocks, the proposed strain-based criteria offer more accurate predictions than the well-known stress-based (PS and MS) criteria.