Effect of thickness on behaviour of E-glass/epoxy composite laminates under low velocity impact

Abstract

Fibre-reinforced composite materials have remarkable potential for use in automobile, aerospace and defence applications due to their high specific properties and stiffness. E-glass fiber reinforced composite laminates are found to be more promising for various defence applications due to their low cost, easy availability, flexibility in design and processing. In the present study, E-glass/epoxy composite laminates were subjected to low velocity impact using 16 mm hemispherical impactor with the impact energy range of 50-150 J. Effect of laminate thickness on impact parameters like peak force, maximum displacement and damage area was experimentally evaluated. It was found that peak force is increased with increase in impact energy up to complete perforation and then became constant. Peak force is found to be increased linearly with the increase in thickness at all impact energies. Maximum displacement has decreased 50% as the thickness of the laminate is doubled. Interaction time/contact duration also decreased due to increased resistance with thickness. Visual inspection of impacted laminates indicates two types of damage regions namely fibre breakage area and delamination area. However, the extent of damage regions and their ratio are found to be thickness dependent. Dominant failure mode gradually changes from fibre breakage to delamination as the thickness is increased.