Kinetic model for prediction of subcritical crack growth, crack tip relaxation, and static fatigue threshold in silicate glass

• Published in: Journal of non-crystalline solids. X Vol. 16; no. C; p. 100134
• Main Authors: Grutzik, S.J., Strong, K.T., Rimsza, J.M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2022; Elsevier
• Subjects: Fracture; Glass; Subcritical; Threshold; Fracture; Subcritical; Glass; Threshold
• ISSN: 2590-1591; 2590-1591
• DOI: 10.1016/j.nocx.2022.100134

Prediction of brittle fracture of amorphous oxide glasses continues to be a challenge due to the existence of multiple fracture mechanisms that vary with loading conditions. To address this challenge, we present a model for all three regimes of crack growth in glasses. Regimes I and III are controlled by Arrhenius processes while regime II is transport controlled along with a simple Arrhenius model for viscoelastic stress relaxation. Through dimensional arguments and physical reasoning, we propose a single mechanism which underlies both regime III subcritical crack growth and near-crack-tip viscoelastic relaxation. By combining the subcritical crack growth and viscoelastic models we obtain a prediction for a threshold stress intensity, Kth, below which stresses around the crack relax faster than it propagates. For stress intensity KI<Kth, no subcritical crack growth is predicted to occur, allowing for the design of stable glass systems. The prediction is compared to measured subcritical fracture threshold data for soda-lime silica glasses.