On the localisation of the FPZ under a pure mode II load identified by a hybrid method

Abstract

In this paper, the fracture process zone (FPZ) of a high-performance concrete (HPC) is studied. The analysis is done under a pure mode II load, making use of a digital image correlation (DIC) technique. The experimental test was performed on Brazilian disc with central notch (BDCN) specimens with a relative notch ratio a/R of 0.267. The main focus of this experimental study was the traction-free crack ahead of the notch tip, together with the FPZ extent ahead of the crack. This is done by adjusting the current method for mode I crack localisation to pure mode II cracks. Additionally, a traditional analytical formulation to predict FPZ length was substituted with the fracture toughness for mode II to cover mode II load cases. To verify the adjustments to the mode I crack identification, crack tip opening (CTOD) and crack tip sliding (CTSD) displacements were measured by DIC, which showed a mode II dominance in the crack tip displacement components.