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 | Hazard Classification Testing of Primers used in Small Arms Ammunition
Author : Bhalla, A.K. ;Uppal, K.S.;Vishvamitra
Source : Defence Science Journal ; Vol:49(1) ; 1999 ; pp 27-30
Subject : 623.45 Ammunition;623.4 Armaments and Ballistics;620.261 Explosives
Keywords : Explosion hazards ;Projectiles;Primers;Initiating devices
Abstract : "Primer is a small initiating device used for ignition of propellant charge and subsequent ejection of projectile from a weapon. Hilherto, primers were classified under safely class. Recent accidents however, have raised doubts about their diversification. Field trials were therefore carried out to ascertain their correct behaviour under different conditions. It was observed that the nature of filling composition, its charge mass and the type of package had profound influence on the hazard classification which could change its classification from safety class to mass explosion hazard. " |
| | Penetration of projectiles in composite laminates
Author : Patel, B. P.;Bhola, S. K.;Ganapathi, M.;Makhecha, D. P.
Source : Defence Science Journal ; Vol:54(2) ; 2004 ; pp 151-159
Subject : 531.55 Projectiles;623.4 Armaments and Ballistics;678 Composite Materials
Keywords : Composite laminates;Penetration phenomenon;FSDT;First order shear deformation theory;Projectiles;Target plates;Ballistic limit;Advanced composite materials;Composite materials;Composite armour;Shear;Deformation
Abstract : This paper deals with the prediction of the penetration phenomenon of a cylindro conical impactor on the Kevlar/epoxy laminated composites using C0 eight-noted serendipity quadrilateral finite element based on first-order shear deformation theory (FSDT). Local as well as global deformations during impact is considered in the evaluation of indentation, penetration and perforation phases. Local strains during impact have been evaluated using the hypothesis made from the available experimental observations of bulging during penetration. A detailed parametric study, considering various projectiles and target plate variables, has been carried out to find their effect on the response of the plate, and ballistic parameters, such as ballistics limit and absorbed energy. |
| | On the remaining velocity of ogival and hemispherical projectiles after penetrating through a certain thickness
Author : Jain, V.K.
Source : Defence Science Journal ; Vol:5(4) ; 1955 ; pp 298-303
Subject : 531.55 Projectiles
Keywords : Hemispherical ;Projectiles ;Ogival
Abstract : Nishiwaki (1951) considered the penetration of conical projectiles. In this paper the author has extended this treatment to the case of ogival and hemispherical nosed projectiles and given an expression for the remaining velocity after penetrating through a certain thickness of the material concerned. |
| | Computational examination of parameters influencing practicability of Ram accelerator
Author : Bhat, Sunil
Source : Defence Science Journal ; Vol:54(3) ; 2004 ; pp 259-270
Subject : 533.6 Aerodynamics;531.55 Projectiles
Keywords : Ram accelerator;Projectiles;Propulsion;Computational fluid dynamics;Modelling;Flow parameters;Projectile velocity;Flow regime;Fuel-oxidiser mixture;Hit probability;Projectile ablation
Abstract : "The problems concerning practicability aspects of a ram accelerator, such as intense in-bore projectile ablation, large accelerator tube length to achieve high projectile muzzle velocity and high entry velocity of projectile in the accelerator tube for starting the accelerator have been examined. Computational models of the processes like phenomenon of projectile ablation, flow in the aero-window used as accelerator tube-end closure device in case of high drive gas filling pressure in the ram accelerator tube have been presented. New projectile design to minimise the starting velocity of the ram accelerator is discussed. Possibility of deployment of ram accelerator in the defence-oriented role has been investigated to utilise its high velocity potential. " |
| | Local damage of plain and reinforced concrete targets under impact load
Author : Khan, U.;Siddiqui, N. A.;Umar, A.;Abbas, H. .
Source : Defence Science Journal ; Vol:53(1) ; 2003 ; pp 67-73
Subject : 620.1 Material Science and Technology;623 Military Science and Engineering
Keywords : Missile penetration;Axisymrnetric impact;Projectiles;Concrete targets;Impact load;Damage assessment
Abstract : In the present study, simplified models for calculating the penetration depth, scabbing, and perforation thicknesses for concrete targets have been proposed. These models consider the dynamic strain rate effect in the estimation of penetration parameters. The results of proposed model have been compared with the experimental data. |
| | Normal and oblique impacts of hard projectile on single and layered plates : An experimental study
Author : Madhu, V.;Bhat, Balakrishna T.;Gupta, N. K.
Source : Defence Science Journal ; Vol:53(2) ; 2003 ; pp 147-155
Subject : 620.1 Material Science and Technology;623 Military Science and Engineering;623.4 Armaments and Ballistics;531.55 Projectiles
Keywords : Projectiles;Normal impact;Oblique impact;Simulations;Layered plates;Target damage;Ballistic limit;Ballistics;Residual velocity;Perforation;Multilayered targets
Abstract : The phenomenon of ordnance velocity impact of projectile on single and layered plates is of interest for many applications. In this paper. an experimental study of normal and oblique impacts or an ogive shaped, hard steel projectile on single and layered plates of mild steel and aluminium is presented. The projectiles were fired at an impact velocity of about 820 ms-1. The plate thickness was varied in the range 10 mm to 40 mm and the ratio of plate thickness to the diameter of the projectile varied in the range 1.5 to 13.0. Observations on target damage and measurements of incident and residual velocities for different angles of impact are presented. Plate thickness t*, for which the incident velocity is the ballistic limit, is determined. Computer simulations were carried out using a hydrodynamic code to simulate the normal impact of a projectile and compared these with the experimental results. Experiments were performed to evaluate the response of these plates of intermediate thickness when layered. and the results were compared to the results of single plate of same total thickness. |
| | Effect of Clamping Rigidity of the Armour on Ballistic Performance
Author : Dikshit, S.N.;Sundararajan, G.
Source : Defence Science Journal ; Vol:42(2) ; 1992 ; pp 117-120
Subject : 623.4 Armaments and Ballistics
Keywords : Armour plates;Ballistic testing;Projectiles;Impact velocity
Abstract : Influence of the manner in which the armour plates are held during their ballistic testing on the armour performance, has been evaluated. One armour plate was clamped rigidly to the test stand while a second plate of identical composition, hardness, and dimensions was hung loosely from the target holder. Both these plates were impacted with the same type of projectiles and over the same impact velocity range. The nature of ballistic damage evaluated indicates that the manner in which the armour is held during ballistic testing has a negligible influence on its performance at least when the mass of the plate is substantially higher than that of the projectile. |
| | Plastic Guidance Fins for Long Rod Projectiles
Author : Bundy, Mark L.
Source : Defence Science Journal ; Vol:47(4) ; 1997 ; pp 473-485
Subject : 533.6 Aerodynamics;623.4.021 Targets;623.4 Armaments and Ballistics
Keywords : Solid propellant ;Projectiles;Target penetration;Aerodynamic drag;Kinetic energy (KE) penetrators
Abstract : Projectile tail fins on long rod kinetic energy (KE) penetrators serve the same purpose as fletchings (feathers) on an arrow, namely, they help align the projectile axis with its velocity vector. This reduces the projectile's yaw and hence reduces its aerodynamic drag. In addition, a low yaw angle at target impact helps to maximise the projectile's target penetration. It is typical for projectiles to exit the gun muzzle and enter free flight at some ndn-zero yaw angle. Aerodynamic forces acting on yawed tail fins create a stabilising torque about the projectile's centre of gravity (CG). This torque can be increased by making the fin material lighter. Most conventional long rod penetrators fired from high performance guns have tail fins made from aluminium. However, aluminium can undergo catastrophic oxidation (rapid burning) in-bore. Coating aluminium with Al/sub 2/O/sub 3/ {hardcoat) prevents ignition of the substrate, provided solid propellant grain impacts do not chip the brittle hardcoat off the surface. Plastic is lighter than aluminium and less exothermic when oxidized. Therefore, other factors aside, it is conceivable that plastic fins could increase projectile stability while incurring less thermal erosion than aluminium. However, thermal loads are not the only concern when considering plastic as an alternative tail fin material. The mechanical strength of plastic is also a critical factor. This paper discusses some of the successes and failures of plastic fins, at least relatively thin fins, for use as KE stabilisers. |
| | Initiation of Detonation in Explosives by Impact of Projectiles
Author : Yadav, H. S.
Source : Defence Science Journal ; Vol:56(2) ; 2006 ; pp 169-177
Subject : 620.261 Explosives ;623.4 Armaments and Ballistics;531.55 Projectiles
Keywords : Detonation;Projectiles;Explosives;Shock waves impact;Projectile impact;Flyer plate projectiles;Flat-ended projectiles;Round-ended projectiles
Abstract : This paper presents a study of initiation of detonation in explosives by the impact of projectiles. The shock wave produced by the impact of projectiles has been considered as the stimulus for initiation of detonation. Three types of projectiles, namely (i) flyer plate, (ii) flat-ended rod, and (iii) round-ended rod or a shaped charge jet, have been considered to impact and produce a shock wave in the explosives. Deriving relations for the parameters of impact-generated shock wave in the explosives and projectiles, and the sound velocity in the compressed explosives, it has been shown that the difference of kinetic energy of the flyer plate before and after the impact, which is equal to the total energy of the shock wave in the explosives, leads to critical energy criterion for shock initiation of explosives. In this study, the critical criterion has been used to derive the relations for initiation of explosives by a shaped charge jet, Vj2 D = K0 , where Vj and D denote the velocity and diameter of the jet, and K0 is a constant of the explosive. |
| | Oblique impact of projectile on thin aluminium plates
Author : Khan, W. U.;Gupta, N. K. ;Ansari, R.
Source : Defence Science Journal ; Vol:53(2) ; 2003 ; pp 139-145
Subject : 620.1 Material Science and Technology;623.4 Armaments and Ballistics;531.55 Projectiles
Keywords : Oblique impact;Impact velocity;Projectiles;Ballistic limit;Residual velocity;Plates;Aluminium plates;Analytical model;Projectile velocity
Abstract : "Experiments were performed, wherein cylindrical projectiles made of hardened steel were impacted on commercially available aluminium plates at different angles. Projectiles were of 12.8 mm diameter and plates were of 0.81 mm, 1.52mm and 1.91mm thicknesses. Based on the experimental results, an analytical model has been developed to predict the residual velocity of the projectile and the ballistic limit of the plate. " |
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