Crack-tip models by Irwin and Dugdale for hydroxyl-damaged crack-tip zones

Due to the hydroxyl generation, the silica network ahead of crack tips is damaged. The consequence is a damaged crack-tip zone showing a reduced Young’s modulus. The linear-elastic fracture mechanical treatment by application of stress intensity factors becomes doubtful especially for large zones. In this report, we use a description via well-known models of Elastic-Plastic Fracture Mechanics, namely, the models by Irwin and Dugdale.
As an application we compared the results with experimental observations on crack profiles from literature. The computed and observed Crack-Tip Opening Displacements (CTOD) were found to be in good agreement.