Citation

Tham CY, Tan VBC, Lee HP. Int. J. Impact Eng. 2008; 35(5): 304-318.

Copyright

(Copyright © 2008, Elsevier Publishing)

DOI

10.1016/j.ijimpeng.2007.03.008

PMID

unavailable

Abstract

Helmet designs have evolved over the last three millennia and the use of helmet may be as old as warfare itself. In 600 B.C. the Greeks in Sparta crafted single-piece helmet from bronze, which provided complete head protection, leaving only narrow slits in front for vision and for ventilation. Later in 250 B.C. the Romans developed several helmet designs, which included the round legionary's helmet and the gladiator's helmet, with broad brim and pierced visor, providing exceptional head, face and neck protection. The use of helmets in battle fields continued until the end of 13th century, which signaled a radical change in the emphasis on head protection. With the invention of gunpowder and the growing effectiveness of firearms over swords and spears, helmets gradually vanished from the battle scenes. The metal helmet that once protected against sword and arrows offers little protection against musket rounds. The United States Civil War provides an excellent illustration—in war soldiers donned cloth hats and caps, with little or no emphasis on head protection. In World War I, the helmet was reintroduced because it protected the head against metal-fragments of exploding artillery shells and indirect fire. The French, owing to General Adrian, were the first to adopt the helmet as standard equipment in early 1915. The British, the Germans, and then the rest of Europe soon followed. In World War I, the German helmet provided the best protection for soldiers. It was manufactured in at least two sizes, and different head contours were accommodated by an adjustable leather lining, which provided comfort and allowed for ventilation. The typical helmet used during that period was a hardened steel shell with an inner liner and weighed about 0.5–1.8 kg. Since then, helmets have been issued to troops in all military conflicts, marking the beginning of the development of modern military helmet. This paper presents the results from experiments and AUTODYN-3D® simulations on the ballistic impact of a KEVLAR® helmet. In the experiment, spherical projectile (~11.9 g), launched from a light gas gun, strikes the helmet with an impact velocity of 205 m/s. The interaction of the projectile with the KEVLAR® helmet is captured using high-speed photography. This helmet-projectile interaction is compared with that obtained from the AUTODYN-3D® simulation. Post-test damage photos from the experiments are also compared with those from the simulations. The response of the helmet from the simulations is consistent with those from the experiments. Also included in this paper are AUTODYN-3D® simulations on two ballistics test standards for KEVLAR® helmets. They are namely the NIJ-STD-0106.01 Type II and the V50 requirement of the US military specification for Personal Armor System Ground Troops (PASGT) Helmet, MIL-H-44099A. For the simulation on MIL-H-44099A, a fragment-simulating projectile (FSP) strikes the helmet with an impact velocity of 610 m/s. The simulation revealed that an impact velocity above 610 m/s is required to perforate the KEVLAR® helmet. For the simulation on NIJ-STD-0106.01 Type II helmet, the projectile is a 9 mm full-jacketed bullet with a striking velocity of 358 m/s. Results from the simulation show that the KEVLAR® helmet is able to defeat a 9 mm full-jacketed bullet traveling at 358 m/s.