Experimental determination of interlaminar GIc using a fully embedded centre-cracked specimen

A new technique is developed to determine mode I interlaminar fracture toughness ( G Ic ) through a circular crack in a plate specimen. The specimen is made by bonding two 2.8 mm thick plexiglass (PMMA) plates with a circular pre-crack at the centre. A tensile machine loads the specimen at a low pulling rate to have slow crack propagation. The theoretical formulation shows that energy release rate ( G I ) is independent of diameter of crack; G I...