Impact damage in polyester-matrix glass fibre-reinforced composites. Part I. Impact damage extent
Michał Barcikowski, Bartosz Semczyszyn
Quarterly No. 3, 2011 pages 230-234
DOI:
keywords: polymer composites, laminates, unsaturated polyester resin, glass fibre, ballistic impact, damage
abstract Fibre-reinforced composites are susceptible to damage resulting from impacts. This damage may lead to a reduction of composite strength and load-bearing abilities, both in static loading as well as during subsequent impact events. Composites with improved tolerance to ballistic impact using inexpensive, common materials i.e. E-glass fibre and unsaturated polyester resin, have been manufactured by means of modern, yet popular moulding technology. Composite materials were reinforced with an E-type glass fibre in the form of a continuous filament mat and woven roving. The fibre content in the composites was varied to evaluate the effect of the reinforcement fraction on impact tolerance. The composites were manufactured using the Resin Transfer Moulding (RTM) method. The extent of damage in glass fibre/polyester composites after non-penetrating ballistic impact has been evaluated. Samples of the manufactured laminates were subjected to impact using a compressed-air gun test assembly. The impactor was a free-flying 3-gram hardened steel sphere, and the impact velocities were up to 125 m/s. After the impact and damage evaluation, the samples were photographed in transmitted light, and the obtained images were digitally processed by software to measure the area of delamination. It was found that the damaged area is directly proportional to the impact energy. Moreover, reinforcement in the form of a continuous-filament mat compares favourably to loose woven roving; such reinforced composites have a much smaller area of delamination after impact of a given energy. The impacted samples were sectioned and imaged microscopically in low magnification. The damage in continuous-filament mat-reinforced composites is visibly less severe than in composites with fabric reinforcement.