Effect of surface treatment on mode I interlaminar fracture behaviour of plain glass woven fabric composites: Part I. Report of the 2nd round-robin test results

A round-robin test programme has been carried out to characterise the mode I interlaminar fracture behaviour of E-glass woven fabric reinforced vinyl ester matrix composites. Special emphasis has been placed on the effect of silane coupling agent on the stability of interlaminar crack propagation an d fracture toughness. Sixteen laboratories participated in this programme. Each laboratory was supplied with composite laminates of thicknesses of its own choice and conducted-the tests according to its own procedures. The re sults showed that variations in interlaminar fracture toughness between lab oratories were very large in spite of slight differences in the test proced ures used, such as specimen dimensions, test speed and data reduction schem es. Nevertheless, the general trends were clearly identified with respect t o different silane coupling agents. Other observations and the implications are discussed.