Mechanisms of penetration in polyethylene reinforced cross-ply laminates

Abstract

A B S T R A C TThe mechanisms of progressive penetration for two ultrahigh molecular weight polyethylene (UHMWPE) reinforced laminates have been investigated. One used an UHMWPE fiber reinforcement while the other utilized molecularly aligned tape. Both materials had similar out of plane compressive strengths, but the fiber system had a 40% higher in plane tensile strength than the tape. Laminated, 6 mm thick plates with a [0°/90°] ply architecture were impacted by a 12.7 mm diameter sphere under conditions that either allowed out of plane plate deflection or eliminated this deflection by rear support of the target. The depth of penetration and the ballistic limit in the rear-supported tests were identical for the two materials, and proceeded by progressive ply failure. However, tests in the edge clamped condition resulted in a substantially higher penetration resistance, especially for the higher tensile strength fiber-reinforced material. Edge clamped testing of a bilayer target, where the front third was composed of the tape material and the remainder comprised fiber reinforced laminate, had the same ballistic limit as a target composed of only the higher ply tensile strength fiber reinforced material. Penetration in both test support conditions was discovered to occur by tensile ply rupture under the projectile, consistent with a recently proposed mechanism for converting out of plane compression to in plane ply tension. Lateral displacement of plies was also observed near the sides of impact craters in both materials, indicating the existence of a second mechanism impeding penetration of the spherical shaped projectile.

Interlaminar shear characterization of ultra-high molecular weight polyethylene (UHMWPE) composite laminates

“…Despite the challenges associated with the accurate characterization of these materials, a good number of investigators have made advances in testing these unique materials. Simple uniaxial tensile tests of [0/90] and [+45/-45] UHMWPE laminates have been successfully performed, but difficulties associated with gripping the material have led to the development of specialized fixtures and specimen configurations to apply the axial loading [1][2][3][4][5][6]. Success has also been reported on the characterization of UHMWPE composite compression behavior [6][7][8] as well as Mode I and II fracture toughness [4,9].…”

Quasi-Static Indentation Behavior of GFRP With Milled Glass Fiber Filler Monitored by Acoustic Emission

“…The progressive penetration mechanism of ultra-high molecular weight polyethylene reinforced cross-ply composite laminates was investigated by O'Masta et al [17]. They observed that sample penetration occurred by tensile ply rupture under the projectile, and higher penetration resistance and onset velocity occurred as the consequence of the sample being end-supported rather than back-supported.…”

Ballistic study of Tensylon®–based panels

“…Different failure mechanisms under bullet penetration occurring in high-modulus high-strength polymeric materials have been revealed in the literature. These mechanisms have been phenomenologically described in several papers such as [1] and [2], and have been highlighted in photographs by various authors, including [3,4]. These mechanisms include cutting of the material fibres or filaments (also known as 'punching' [1]), stretching accompanied by deflection of the panel, friction between the bullet and its surrounding, energy transfer by the waves away from the impact, etc.…”