Comparative Evaluation of Impact Performance of Laminate Composites Containing Impact Induced/Mechanically Inserted Defects

The low mass, low energy pendulum impact on carbon-epoxy (C-E) composite system under varied conditions are reported in this work. While in one case repeated low mass impacts were followed by a single higher mass impact leading to failure, in others, between these two impact events, slits of depth 1 mm, 3 mm and 5 mm were introduced. Also, in one experiment a variation in the programme involved a 45° notch being inserted instead of the slits. Fracture features were also examined using a light microscope.

For the case of unnotched specimens, the investigation points to a maximum energy absorption and a fracture surface which is grooved with a rough terrain. The data, on the other hand, point to a minimum energy absorption and a comparatively flat feature for the fractured surface for the case of 5 mm slit introduced specimen. Samples with other depths of slits showed features that lie in between these two extremes.