Analysis of notch effect in PMMA using the Theory of Critical Distances

The Theory of Critical Distances is actually a group of methodologies, all of them using a characteristic material length parameter when performing fracture assessments on any kind of stress risers. In this paper, the application of the Theory of Critical Distances on Polymethyl methacrylate is analysed, the parameters involved in the analysis are calibrated, and the different versions of this theory are applied, with satisfactory results, to the prediction of the notch effect on the apparent fracture toughness measured on notched specimens. Also, a Scanning Electron Microscopy analysis is performed, establishing relations between the fracture mechanisms and the predictions provided by the Theory of Critical Distances.

► The application of the TCD on PMMA has been validated. ► Some precautions are proposed when performing the calibration of the TCD. ► The calibration of the TCD can be performed in two ways leading to similar results. ► The evolution of KIN is caused by the evolution in the fracture mechanisms.