Impact response of woven glass-fabric composites - I. Effect of fibre surface treatment

Instrumented impact tests have been employed to study the impact response of vinyl-ester-matrix composites reinforced with woven E-glass fabric. Special emphasis has been placed on an evaluation of the extent of damage and the residual mechanical properties as affected by five different fibre surface treatments. Substantial differences are noted in the shape, mode and area of damage between the front and back surfaces of impact and between the laminates with different fibre surface treatments. Compression-after-impact (CAI) tests were performed to measure the residual compressive strength. A simple model is adopted to predict the threshold impact energy and the threshold damage below which no degradation in residual compressive strength occurs. The major conclusion of the work is that an increase in the γ-MPS silane concentration improves the damage resistance and damage tolerance of the laminates in terms of incipient energy, threshold energy and threshold damage width.