Notch depth and root radius effects on quasi-brittle fracture of materials related to grain size

Abstract

Fracture of quasi-brittle materials is sensitive to geometry of defect (e.g. notch). In this study, an analytical model predicting fracture stress of specimen is proposed to consider notch depth and root radius effects which are related to average grain size G by analyzing facture measurements on ten ceramics (G: 1–500 μm) and four rocks (G: 300–810 μm). In addition, normal distribution theory is incorporated to describe the inevitable scatter of fracture measurements due to material heterogeneity and/or machining/testing errors. The results show that the proposed model can reliably predict fracture behavior of notched specimens with 96% reliability.