Punch problem for initially stressed neo hookean solids

The paper reports the indentation of a semi-infinite, initially stressed elastic medium under the action of an axisymmetric rigid punch pressing the medium normally. Th~ problem has been considered within the framework of incremental deformation theory for neo-Hookean solids. Using the Hankel's transformation, the distributions of incremental stress and strain have been obtained. Indentations by a flat-ended c and a conical punch have been obtained as special cases and these effects have been studied numerically and presented in the form of curves. This problem has defence application as many launching pads and firing machines have some neo-Hookean solids as buffer which bear enormous impact or punch during the action of the machine

Rupture of Human Skin Membrane under Impact of Parabolodial Projectile: Bullet wound Ballistics

This paper attempts to study the effect of the impact of a paraboloidal projectile on human shin membrane. The tip of the projectile (i.e., the bullet tip) has been considered to be paraboloidal and is made of lead or steel. The threshold velocity i.e., the velocity when the skin membrane is about to rupture has been calculated for human beings of various age groups. The threshold velocity for a paraboloidal projectile of certain dimensions has been found, for all age groups, to be less than that of a spherical projectile under similar conditions