Conical and hemispherical nose-shaped cylindrical impactors have been used in drop weight impact experiments on 3.1 mm CSM-polyester laminated plates. Based on experimental results, various failure mechanisms and energy absorbed in different failure modes are identified and calculated. It is found that the damage area beyond a certain value of impact energy does not increase. The perforation geometry is the same as that of the impactor irrespective of increased crack length, and complete rotation of petals takes place at impactors radius. It is also observed that the crack length increases with decrease in contact area. But, when the nose is sharp (5 mm hemispherical nose), there is no extended crack beyond perforated region. Blunt nosed (truncated conical impactor with 10 mm nose dia) impactors cause more number of petals/cracks than 10 mm hemispherical nosed impactor and less than 5 mm hemispherical nosed impactor. The petals formed by a cylindrical impactor with 40 mm hemispherical nose are unequal in size, whereas in the case of conical impactors, these are equal. At lower energies, blunt nosed impactors cause more delamination than the hemispherical ones, and at higher energy, it is the reverse. It is found that there exist many visible concentric circular ring hinge mechanisms at the top surface of plates.
Composite plates, impact, penetration, nose shapes, energy absorption
