The energy-absorbing mechanisms built in the composite include (Uma Devi et al.

1997) :

1. Utilization of the energy required to de-bond the fibers and pull them completely out of the matrix

2. Use of a weak interface between the fiber and the matrix

Impact resistance and strength are determined from the Charpy impact test con­ducted on IDL FRP composite specimens, and the results are graphically plotted in Fig. 8.16. Complete break of specimens is observed at all the fiber volume fractions.

An impact strength 18.94 kJ/m2 is obtained for IDL FRP composites at maximum fiber volume fraction. The impact strength of the IDL FRP composites is increasing with increase in fiber volume fraction. PALF FRP composites had exhibited similar kind of behavior, where the impact strength of the composites was found to increase linearly with the weight fraction of the fiber.