Showing papers on "Ballistic impact published in 2000"
TL;DR: In this paper, the authors developed a simple model for calculating the energy absorption by polymer composites upon ballistic impact, where three major components were identified as contributing to the energy lost by the projectile during ballistic impact.
287 citations
TL;DR: In this paper, a simple model was developed to explain the bi-linear behavior and to provide the basis for geometrical scaling of composite ballistic perforation data, and also to help with the interpretation of material parameter and bond strength influences on ballistic resistance.
151 citations
TL;DR: In this paper, a sheet of laser light is progressively blocked and unblocked by the projectile, and the corresponding change in total intensity is measured and converted to a displacement-time curve.
54 citations
TL;DR: In this paper, the problem of two-component ceramic-faced lightweight armors design against ballistic impact is solved using Florence's model, and approximate analytical formulas are derived for areal density and thicknesses of the plates of the optimal armor as functions of parameters determining the properties of the materials of the armor components, cross-section and mass of an impactor, and of the expected impact velocity.
29 citations
01 Jan 2000
7 citations
TL;DR: In this paper, a numerical model incorporating post-failure response was implemented in the LS-DYNA explicit dynamic finite element code to predict the penetration and backplane response of the composite material under ballistic impact.
Abstract: The ballistic impact response of woven composite helmet materials was analysed both experimentally and numerically. Ballistic impact tests were performed on flat panels, using different projectiles with a range of impact velocities. The p penetration and backplane response of the composite panels were measured. A numerical model incorporating post-failure response was implemented in the LS-DYNA explicit dynamic finite element code to predict the penetration and backplane response of the composite material under ballistic impact. Close agreement was found between the simulated backplane displacement and the data obtained from the ballistic experiments. A linear relationship was observed between the maximum backplane displacement and the impact energy, at least within the range of impact energies considered. The model presented this study will be used to assess the degree of improvement in performance of current ballistic protection offered by design changes and the adoption of new materials.
4 citations
TL;DR: An existing family of composites of steel chains in resin matrices that exhibit delocalized failure and high levels of energy absorption under static tensile loading has been tested under high-velocity impact conditions.
3 citations
01 Oct 2000
3 citations
Patent•
07 Jun 2000
TL;DR: In this article, an outer layer of a composite of high tensile fibres together with a ductile polymer binder is held in place adjacent to the inner layer, such that the material can stretch to trap any shrapnel which may penetrate the inner layers.
Abstract: A composite armour material comprises an outer layer of steel material with a hardness between 47 ad 54 (Rockwell "C") and an inner layer of steel material with a hardness of between 28 and 36 (Rockwell "C") and a fracture toughness of 3.6 - 6.5 J/mm. The outer layer absorbs the ballistic impact of a projectile, and the inner layer absorbs the blast. The two layers are bonded together, preferably with a synthetic resin bonder such as a polysulphide based material or a polyurethane based material. A further layer of a composite of high tensile fibres together with a ductile polymer binder may be held in place adjacent to the inner layer, such that the material can stretch to trap any shrapnel which may penetrate the inner layer. A further outermost layer of applique material may also be attached, comprising two layers of mild steel sandwiching a layer of ceramic tiles.
1 citations
01 Jan 2000
TL;DR: In this article, the impact energy had the largest influence on the response of gamma-TiAl to ballistic impacts, while the Hertzian crack length was the best predictor of residual fatigue strength.
Abstract: The ability of gamma - TiAl to withstand potential foreign and/or domestic object damage is a technical risk to the implementation of gamma - TiAl in low pressure turbine (LPT) blade applications. The overall purpose of the present study was to determine the influence of ballistic impact damage on the high cycle fatigue strength of gamma - TiAl simulated LPT blades. Impact and specimen variables included ballistic impact energy, projectile hardness, impact temperature, impact location, and leading edge thickness. The level of damage induced by the ballistic impacting was studied and quantified on both the impact (front) and backside of the specimens. Multiple linear regression was used to model the cracking and fatigue response as a function of the impact variables. Of the impact variables studied, impact energy had the largest influence on the response of gamma - TiAl to ballistic impacting. Backside crack length was the best predictor of remnant fatigue strength for low energy impacts (<0.74J) whereas Hertzian crack length (impact side damage) was the best predictor for higher energy impacts. The impacted gamma - TiAl samples displayed a classical mean stress dependence on the fatigue strength. For the fatigue design stresses of a 6th stage LPT blade in a GE90 engine, a Ti-48Al-2Nb-2Cr LPT blade would survive an impact of normal service conditions.