Geometrical effects in the low velocity impact response of GFRP

The suitability of damage–force maps for characterising low velocity impact damage in a glass fibre reinforced polyester composite has been investigated at low and intermediate energies. Tests were undertaken on circular plates with diameters ranging between 50 and 300 mm and on square plates with edge lengths of 75 and 200 mm. Damage took the form of delamination under the point of impact and more widespread matrix cracking. The translucent nature of the composites facilitated the determination and quantification of the extent of damage within each specimen. Plots of delaminated area against impact force yielded maps in which the experimental data lay within a narrow band over the range of conditions examined. For a given impact energy, the impact force was greater and damage was more severe in smaller coupons. The damage–force maps suggested that the impact force to generate delamination lay between 600 and 800 N in spite of the fact that largest structure was over 35 times larger than that of the smallest structure investigated. An energy–balance model was used to successfully predict the impact response of the circular structures and to predict the onset of damage within these composite plates.