An experimental evaluation of glass–polymer interfacial toughness

The evaluation of interfacial fracture toughness in glass fibre reinforced polymer composites is examined using macroscopic polymer–glass joints. Different bi-material systems providing various degrees of mixity were tested using various tests configurations. The test configurations were analysed in the frame of interfacial linear elastic fracture mechanics with the finite element method in order to investigate their properties and obtain relations between fracture mechanics parameters and joints’ geometry useful for the experimental data reduction. The analysis showed that the stress intensity factor phase angle characterizing mode mixity is almost constant with crack length for each test configuration examined: hence these tests lend themselves to be used to study the crack propagation behaviour when stable crack growth is observed.Joints made of combinations of E-glass, either treated or untreated with a surface finishing agent, and two polymers, poly (methylmethacrylate) and an epoxy resin, were employed.An attempt to model the fracture process of these systems with cohesive elements yielded not completely satisfactory results.