Experimental procedure to characterize the mode I dynamic fracture toughness of advanced epoxy resins

This research aimed at developing an experimental procedure to characterize the dynamic fracture toughness of a fast running crack in advanced epoxies enriched with thermoplastic particles and demonstrating quasi-brittle fracture. A strain gauge method was defined to determine the dynamic stress intensity factor K ID for the mode I crack opening with various crack speeds. This strain gauge measurement was associated with high speed cinematography on a three point bending test dedicated to the fracture of notched specimens made of the Hexply®M21 epoxy resin. Results demonstrate that the crack propagation speed has a large influence on the dynamic fracture toughness of advanced epoxy resins.