Influencing Parameters on He Projectiles with Natural Fragmentation (original) (raw)
Related papers
2011
This research paper presents numerical studies of the characteristics of warhead fragmentation in terms of initial velocities, spray angles of fragments and fragment mass distribution of high explosive (HE) warhead. The behavior of warhead fragmentation depends on shape and size of warhead, thickness of casing, type of explosive, number and position of detonator, and etc. This paper focuses on the effects of material properties of warhead casing, i.e. failure strain, initial yield and ultimate strength on the characteristics of warhead fragmentation. It was found that initial yield and ultimate strength of casing has minimal effects on the initial velocities and spray angles of fragments. Moreover, a brittle warhead casing with low failure strain tends to produce higher number of fragments with less average fragment mass.
Lethal Influence Factors of Natural and Preformed Fragmentation Projectiles
DAAAM International Scientific Book, 2015
Low intensity warfare had many impact on reducing logistic costs during field operations. It influenced the development of new large caliber HE projectiles. Concerning increasing lethal efficiency at target, the focus is at development of modern projectiles with natural, embossed and preformed fragmentation. Modern natural fragmentation projectiles characterize excellent aerodynamic properties, use of high strength steel with high fragmentation characteristics and denser high energy materials. Artillery projectiles with preformed fragments are usually equipped with large amount of preformed spherical or cubical fragments made of steel or tungsten. Modern unguided rocket warheads are based on embossed fragmentation or preformed warheads concept. There are limited data about real lethal effects of these projectiles. This paper presents available data and research results of embossed fragmentation warhead 122 mm and prefragmented warhead 128 mm, which are conducted in Bosnia and Herzegovina.
Journal of KONES. Powertrain and Transport, 2016
The article presents results of the numerical analyses of the fragmentation warhead, which is one of the key elements of the missile used to combat anti-tank missiles. The fragmentation warhead is composed of such elements as outer casing, inner casing, explosive material and fragmentation liner. The fragmentation liner is built from steel spheres or cylinders embedded in epoxy resin. As a result of the explosive material detonation the pressure wave is generated, which affects the liner, causes its fragmentation, and drives each splinter. In order to perform numerical analyses the model of the cylindrical fragmentation warhead with a diameter of 80 millimetres and a length of 100 mm was prepared. The fragmentation liner consists of steel spheres with a diameter of 5 mm. It was assumed in simulation that the detonating material is the plastic explosive C4. The influence of the position of the explosive charge detonation initiation point of the fragmentation warhead on its effectiveness was studied. Effectiveness was evaluated by measuring the maximum speed obtained by the fragments and their spatial distribution. A threedimensional model of the studied system has been prepared using the MSC Patran software and the numerical analyses were performed using the finite element method with explicit scheme of the time integration implemented in the LS-Dyna solver. To model gas domain Arbitrary Lagrangian-Eulerian (ALE) method was used and interaction between gas and solid body was modelled with FSI coupling.
Characterization of distribution parameters of fragment mass and number for conventional projectiles
Assessment of parameters of high explosive (HE) projectile fragmentation process (mass distribution and number of fragments) in most of the scientific papers is generally best de-scribed using Mott (depending on dimensionality and different scaling models) and Held equations. These methods can describe mass distribution of fragments excellent, but pre-cise data about individual parameters from these equations are not available in public lit-erature. During the previous eksperimental research of natural fragmentation for several types of HE projectiles, authors are studied the effects of several types of projectile body materials, two types of high explosive and projectile design and determined range of pa-rameters using in Held laws. Obtained data can help designers with smaller experimental experience to make faster prediction of new projectile fragmentation parameters.
Comparison of Lethal Zone Characteristics of Several Natural Fragmenting Warheads
Research of HE warheads lethal zone is very complex topic because of large number of controlled and independent, sometimes correlated, influencing factors. Capability for prediction of lethal zone is based on complexity of databases regarding natural fragmentation parameters, which should contain data about warhead body material characteristics, types of explosive charge, number, mass, initial velocity and spatial distribution of fragments, battlefield terrain, distribution of soldiers on battlefield, etc. Based on experimental research (fragmentation test in Arena facilities with two types of artillery projectiles and two types of rocket warheads), analytical and numerical methods used -projectiles lethal zones are predicted and analyzed. Influence of projectile design and explosive charges on warhead lethal zone is analyzed.
Fem Simulation Of He Blast-Fragmentation Warhead And The Calculation Of Lethal Range
2012
This paper presents the simulation of fragmentation warhead using a hydrocode, Autodyn. The goal of this research is to determine the lethal range of such a warhead. This study investigates the lethal range of warheads with and without steel balls as preformed fragments. The results from the FE simulation, i.e. initial velocities and ejected spray angles of fragments, are further processed using an analytical approach so as to determine a fragment hit density and probability of kill of a modelled warhead. In order to simulate a plenty of preformed fragments inside a warhead, the model requires expensive computation resources. Therefore, this study attempts to model the problem in an alternative approach by considering an equivalent mass of preformed fragments to the mass of warhead casing. This approach yields approximately 7% and 20% difference of fragment velocities from the analytical results for one and two layers of preformed fragments, respectively. The lethal ranges of the si...
Very important task of HE projectile terminal ballistics is determination of lethal area. Lethal area is a measure of fragment casualty-producing potential of an exploding projectile when employed against human targets, and can be expressed as a function of soldiers density and probability that the personnel will be incapacitated. Researchers worldwide use different criteria for human target densities. It means that expected number of casualties, after detonation of single projectile, will strongly depend on chosen criteria for soldiers density on terrain. In our model, based primarily on U.S. Vulnerability Model, lethal zone of HE warheads is defined as a zone on the battlefield in which an efficient fragment density is greater or equal to 1 frag/m 2 . That means that the Isodensity curve [9] , a curve which connects points with the same efficient fragment density, presents an envelope of HE warhead lethal zone. Soldiers standing inside of lethal zone will be incapacitated by an ef...
Numerical Modeling of Rocket Warhead Detonation and Fragmentation
Numerical models provide a safer and more cost-effective method to evaluate the performance of military warheads and weapons systems. These simulations are increasingly employed for military research and development. The scientific community must be confident in the accuracy of these computations, and thus analysts need to continually validate numerical models. This paper presents results from a numerical study of the detonation and fragmentation of a rocket warhead commonly found throughout the world. ...
Brazilian Journal of Chemical Engineering
The wide usage of TNT as a main charge for fragmentation shells has been eliminated due to its lower performance and exudation on the fuze thread and relevant safety measures inconvenience. These disadvantages have not become accepted anymore due to the desired safety requirements and the limited efficiency of the TNT, especially when different new explosives are introduced into researches. This research studies the fragmentation calculations of the 120 mm high explosive shell when its is loaded with different explosives rather than TNT. Different explosives have been used in the current research include the melt cast compositions such as Octol and composition B, a cast cured composition based on RDX with HTPB polymer matrix and the plastic explosive composition HMX-silicone. The fingerprint of the fragmentation pattern of each shell loaded with different explosive has been obtained using Autodyn smooth particle hydrodynamic (SPH) algorithm, whose numerical model has been validated ...
This paper deals with high explosive projectile reproduction process over several years of monitoring and testing its fragmentation characteristics. Experimental data used in analy-sis were obtained using PIT tests in our country. Many fragmentation tests were conducted with 19 different production series of projectile mortar projectile 120mm M62, in a time span of over three years. Number, mass and fragments shape of each fragment mass group are determined using the PIT test. In PIT test, warhead is detonated in closed space, filled with sand. After the fragmentation of warhead, fragments are obtained from the sand. Mass and shape of fragments are determined, and fragments are classified by their mass groups. Number of methods is available for prediction of fragment mass distribution, and one of these is method introduced by M. Held. Authors tried to find variations in reproduction process of projectile, using statistical pa-rameters of given tests. In order to analyze possible sig...