Abstract
In the recent past, shaped charges have dominated the weaponry market apparently due to their effectiveness in achieving deeper penetration of the targets. Military officers are increasingly adopting it in warfare. Shaped charges have a long history since they emerged in the 18th century. At the time, they were being used by miners before being recognized as weapons. As technology advanced, modern charges evolved. Such charges are now being used for warfare purposes. The recent embracement of charges for mining and warfare purposes has prompted research to uncover the technology that makes them effective. Consequently, the literature regarding the mechanics of shaped charges has grown tremendously. This paper explores the modern shaped charges to inform the reader about their operations. To achieve the stated objective, the paper gives a comprehensive definition of shaped charges, its mechanics, and its application in the military. The paper will then compile a conclusion, which will be a summary of the themes discussed.
Introduction
Shaped charges refer to some special types of explosives, which are perforated on the attacking side. The perforated charges take different shapes. They may be conical, hemispheric, or trumpet fashioned (Held, 2001). Shaped charges were originally used in mining, particularly making holes on rocks to facilitate the digging of minerals. Today, their application has expanded to other areas such as demolition of buildings, making steel products, and perforation of holes on hard services. In addition to the highlighted areas, the charges are increasingly being used in the military for warfare purposes. Their application in warfare commenced after the Second World War when the weapons used in the fight became advanced. Shaped charges are made up of different elements, which are designed to cause the jet to penetrate deep inside the target.
A basic charge has a detonator on one side and a highly reactive explosive on the other. When the unstable paraphernalia is discharged, waves of high frequencies are produced. The waves travel towards the apex of the liner where they cause it (liner) to deform by releasing a high-speed jet (Lim, 2013). Once the jet gets into contact with the target, it exerts pressure on it and produces heat (Goto et al., 2007). Factors such as the high amount of heat coupled with high pressure make the jet penetrate deep inside the target, thus leaving a hole behind. The working of shaped charges has dominated the current studies. However, most studies have not fully explored the operations of the device. This situation leaves a gap in knowledge regarding the device. To seal the gap, this paper explores the operations of shaped charges to gain insight into their mechanisms and their application in the modern world.
Mechanics of Shaped Charges Jet
The mechanics of a shaped charge may be understood well theoretically since literature is available concerning the topic. As shown in Figure 1, a shaped charge is made up of different parts that are fashioned to perform a certain purpose.
The figure depicted in the diagram denotes various components that make up a shaped charge. According to Ouye, Boeka, and Hancock (2007), part 1 denotes the Aerodynamic coat. Parts 2, 3, 4, 5, and 6 denote air-filled space, pointed facing, detonator, unstable section, and piezoelectric activator respectively. A basic charge usually contains a volatile section at one end and a detonator at the other end (Shi, Luo, Li, & Jiang, 2016). The other feature common in shaped charges is the liner, which appears in a conical shape, although it can also appear in other different forms such as hemisphere, tulip, or trumpet among others. The liner is made of aluminum. However, at times, it is made of other similar metals such as zirconium, steel, and uranium (Saran, Ayısıt, & Yavuz, 2013). The apex of the liner is in direct contact with the detonator. It initiates the process of ejecting the charge. Once the charge is ignited, an express wave is generated. The signal moves from left to right, thus causing the expansion of the surrounding casing, which consequently causes crumbling. The wave takes an estimated order of 6Āµs to reach the apex of the liner where it causes the facing to cave in to its axis. The collapse of the liner results in the formation of a jet, which is then discharged, typically traveling at a speed six to twelve kilometers per second (UgrÄiÄ & UgrÄiÄ, 2009). The jet continues to long before it reaches the target.
Owing to the high pressure exerted on the target by the tip of the jet, a plasticity effect is created. The exact temperature resulting from the contact between the jet and the target is not well known. However, some researchers argue that the average temperature on the surface of the target because of the contact with the jet is approximately 500oC. The towering temperatures coupled with the high pressure exerted on the target cause the jet to infiltrate deep inside the target. As the jet penetrates inside the target, it causes radial expansion of the target, thus facilitating the infiltration of the jet inside the predetermined object. After the jet finally comes to a halt, it is argued that the mass before and after the penetration is the same.
Applications of Shaped Charges in Military
In traditional times, shaped charges were used for non-warfare purposes. One of the roles that the devices performed included digging holes on rocks for mining purposes. The device has the power to penetrate in hard metals and rocks and hence the reason why it was suitable for perforating rocks during mining. The device would pierce on the rocks as a way of making it reach the desired minerals. Following the evolution of the atomic bombs and their use in World War 2, it became necessary for armed forces to device better weaponry to deal with the enemies. Consequently, shaped charges were introduced in the military to act as bombs. One of the reasons for the adoption of shaped charges for warfare purposes was due to their speed and linearity. As described previously in this paper, shaped charges can follow a straight line. Hence, it is impossible to miss the target. The ability to move in a straight line is attributed to the fact that the jet originates from a deformation of the liners. Once the liners are distorted, the asymmetric path is formed at the center of the conical liners. The jet tends to follow the path even after its discharge into the air. Therefore, a military person using the device to fire at a target cannot miss it. Additionally, the speed at which the jet travels prevents its diversion.
Currently, most of the military weapons utilize the shaped-charge technology, which makes them effective in warfare. However, as opposed to the traditional warheads, which were not effective, the modern ones are efficient to the extent that they penetrate deeper inside the target (Lim, 2012; Voitenko, Goshovskii, Drachuk, & Bugaets, 2013). The ineffectiveness of traditionally shaped charges was attributed to the poor technology that was used to construct the warheads at the time. For example, the precision and detonators were inferior to the extent that their condition did not favor the linear movement of the jet (Kobylkin, 2015). This situation caused a diversion, which made the device penetrate lightly on the target. The modern application of shaped charges in the military includes its application in high explosive anti-tank (HEAT) (Homel, Guilkey, & Brannon, 2015). The mentioned device uses similar technology as the shaped charges. It is used in anti-tank guided missiles, unguided rockets, gun-fired projectiles, rifle grenades, land mines, and torpedoes among others.
Hydraulic Pressing Process of Shaped Charges
The shaped charges follow the Pascal principle, which argues that the stress exerted on one point of a blocked system is distributed equally in the entire object (Mahdian, Ghayour, & Liaghat, 2013). Based on the Pascal principle, the pressure exerted by the high-frequency waves emanating from the explosives is disseminated uniformly in the whole service of the liners. Consequently, each section of the liner is subjected to the same amount of pressure from the waves. The result is that the liners are deformed at once, a situation that causes asymmetric lines originating from the apex. The linear path is the one that the jet uses to travel without diverting. This situation reduces the chances of missing the target since the jet cannot be diverted before it reaches its target. If the principle of Pascal did not apply in the shaped charges, the liners would be deformed at different times. The pressure on either liner would not be the same. This situation would result in a non-straight path for the jet, a case that would consequently lead to missing the target. Additionally, the ability of shaped charges to penetrate the target would be adversely affected due to its diversion. As noted previously in this paper, the effectiveness of shaped charges is determined by its ability to infiltrate deep inside the target. Therefore, the diversion of the device would make it ineffective.
Effect of the Density Distribution of Explosive on the Performance of Shaped Charges
Explosives that are inside the charges need to be asymmetrical to produce the desired effect (Zellner & Vunni, 2013). The density of the explosives must be identical for the device to function properly. If the explosives are not identical, the performance of the device will be adversely affected. In cases where some of the explosives are denser compared to others, the apex of the linear path will not be accurately targeted when detonating the device. Consequently, waves that will be produced from the process will have varying frequencies, thus leading to inappropriate deformation of the liner (Han & Du, 2007). As noted previously in this paper, the linearity of the jet is caused by the systematic deformation of the liners. If the liners are deformed at different intervals, the jet will not follow a straight line. This situation may cause light penetration of the target (Shvetsov, Matrosov, & Stankevich, 2015). In persistent cases, the jet may miss the target, meaning that it will not achieve its objectives.
Conclusion
Shaped charges refer to a device that is perforated on one end. When fired, the gadget establishes a hole on a target. Shaped charges are known to penetrate deeply even in surfaces that other types of perforators cannot infiltrate. The shaped charges were invented in the 18th century. They were mainly used by miners to make holes on rocks. The charges were more effective relative to the traditional devices that were used for mining. Since their discovery, the roles of the charges have evolved tremendously. They are now very different from traditional mining roles. Today, they are being used in the steel industry to make holes on metals for different purposes. Additionally, shaped charges are increasingly being used in the military for warfare purposes. The design of the shaped charges is important to the working of the devices. Typically, a basic charge has a detonator on one side and a highly reactive explosive on the other. When the explosive is ignited, waves of high frequencies are produced. The waves travel towards the apex of the liner where they cause the liner to deform, thus releasing a jet that travels at a very high speed. Once the jet gets into contact with the target, it not only exerts pressure on it but also produces heat. The high amount of heat coupled with the high pressure causes the jet to go through the target, thus leaving a hole behind.
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