Volume 20, Issue 5, 2011
LETTER:INFLUENCE OF PROJECTILE NOSE SHAPE ON BALLISTIC LIMIT AND DAMAGE TO GLASS/VINYL ESTER COMPOSITE PLATES
M. Sasikumar1 , V. Sundareswaran2
1Research Scholar, Department of Mechanical Engineering, Anna University, Chennai -25. India.
2Professor, Engineering Design Division, Anna University, Chennai -25. India
Received 1 June 2011; accepted 28 July 2011
In the recent past, the substantial structural strength, light weight and stiffness properties of polymer based composite materials find its application in
aircraft and automotive structures at prodigious rate. Fibre glass Reinforced Plastic (FRP) composites are partially elastic and brittle. The present study
evaluates the ballistic limit, energy absorbed and the damage area caused by different projectile nose shapes on the composite plates made of glass fibre and
vinyl ester resin with the orientation of (0/90)s . The number of plies in the plates is varied to 4, 6 and 8 and thus lead to different thicknesses. The
projectile nose geometry is varied (hemispherical, conical, truncated conical, ogival and truncated ogival) to have realistic effect on the impact. The
influence of projectile nose shape over ballistic limit is found experimentally and compared with the analytical predictions by H. M. Wen [5,6]. The
ballistic limit, perforation mechanism, energy absorption at ballistic limit and the damage area at ballistic limit velocity has been studied. The
influence of thickness of the composite plate over the ballistic limit have also been discussed. It is found that the truncated conical nose shaped
projectile resulted in highest ballistic limit and largest damage area dominated by delamination. Experimental results showed that the analytical
method [5,6] could satisfactorily predict the ballistic limit.
Keywords:composite plates, projectile shape, thickness of the plate, ballistic limit and the damage area.