On the penetration energy for fibre-reinforced plastics under low-velocityimpact conditions

This paper dears with the prediction of the penetration energy for fibre-re inforced plastics subjected to low-velocity impact. Some results available in the literature, allowing evaluation of the main parameters affecting the energy-absorbing capacity of a composite laminate, are reviewed first. It is shown that, for a given fibre type, the penetration energy is substantia lly influenced by the total fibre volume and tup diameter, whereas other fa ctors, such as resin type and content, fibre architecture, stacking sequenc e and orientations, play a secondary role in the phenomenon. An empirical p ower law equation recently proposed by the authors, from which the penetrat ion energy can be evaluated, is then assessed on the basis of experimental data previously published. The results indicate that the exponent of the po wer law is probably independent of the material considered, being practical ly the same for carbon- and glass-fibre-reinforced plastics, and even for a n isotropic material such as polycarbonate, prone to extensive plastic yiel ding before final failure. The formula proposed, useful for in-plane isotro pic and moderately anisotropic composites, can also permit the comparison o f impact data generated under different impact conditions. (C) 2000 Elsevie r Science Ltd. All rights reserved.