Gun Barrel Research Articles

A Research on Characteristics of Internal Flow Based on the Gun Barrel Length and Ammunition Pressure.

A Research on Characteristics of Internal Flow Based on the Gun Barrel Length and Ammunition Pressure.

The modal analysis of three-dimension gun barrel using isogeometric analysis and its application to optimization

In this paper, the Isogeometric Analysis (IGA) is applied to make the modal analysis for 3D gun barrel. The geometry of IGA is modeled by None-Uniform Rational B-Splines (NURBS) which is exact and smooth even at the coarsest mesh level. The first 9 natural frequencies were calculated respectively by IGA and traditional finite element method (ABAQUS), and compared with the test results. The maximum relative error between numerical value and experimental value is less than 3.6 % which verifies the feasibility of numerical model. Six different refinement schemes were analyzed to compare the computational accuracy and efficiency of IGA and ABAQUS. To achieve the credible results, the CPU time of ABAQUS is more than twice of IGA. On this basis, the IGA method is used for the structural shape optimization of gun barrel. The first natural frequency is increased by 6.96 % and the barrel mass is reduced by 4.9 %.

Artillery Guns of the 16th–18th Centuries in Lithuanian Museums and a Private Collection

This article discusses all the original 16th–18th c. artillery guns kept and displayed in Lithuanian museums and a private collection. The guns have been grouped in accordance with their types, dates of manufacture and their storage/display locations. There are also data provided by the X-ray fluorescence (XRF) analyses of gun barrel alloys’ chemical elements. The text is supplemented by a catalogue of the abovementioned artillery guns.
 Keywords: artillery, kartouwe, culverin, bombard, howitzer, mortar, swivel cannon, field cannons

Robust Microencapsulated Silicone Oil with a Hybrid Shell for Reducing Propellant Erosion

AbstractA morphologically stable silicon oil microcapsule base polystyrene as shell modified with TiO2 and Si3N4 nanoparticles was synthesized, characterized and applied as an inhibitor for high energy propellant to reduce erosion of gun barrel. The composite microcapsules were obtained by an eco‐friendly method. Embedding heat‐resistant TiO2 and Si3N4 nanoparticles in polystyrene shell enhances the reliability of polymeric shell. The anti‐erosion effect of composite microcapsules for high energy propellant was investigated by using an erosion tester. Results showed that the erosion property of high energy propellant with composite microcapsule was significantly decreased when compared to control sample (without microcapsules). It showed a decrease of 20.6 % in erosion mass when 7 wt.% of composite microcapsules were added to the high energy propellant. Moreover, the anti‐erosion efficiency of composite additives exhibited an increasing trend with the increase of their contents. The pressure and time history confirmed that the composite microcapsules also have ability to adjust the combustion performance of high energy propellants. The developed silicon oil microcapsule shows a potential application for propellant erosion additive.

Automatic matching of bullet land impressions

In 2009, the National Academy of Sciences published a report questioning the scientific validity of many forensic methods including firearm examination. Firearm examination is a forensic tool used to help the court determine whether two bullets were fired from the same gun barrel. During the firing process, rifling, manufacturing defects, and impurities in the barrel create striation marks on the bullet. Identifying these striation markings in an attempt to match two bullets is one of the primary goals of firearm examination. We propose an automated framework for the analysis of the 3D surface measurements of bullet land impressions, which transcribes the individual characteristics into a set of features that quantify their similarities. This makes identification of matches easier and allows for a quantification of both matches and matchability of barrels. The automatic matching routine we propose manages to (a) correctly identify land impressions (the surface between two bullet groove impressions) with too much damage to be suitable for comparison, and (b) correctly identify all 10,384 land-to-land matches of the James Hamby study (Hamby, Brundage and Thorpe [AFTE Journal 41 (2009) 99–110]).

From Gun Barrel to Passport: Smuggling on the Turkish-Syrian Border

Syria, which has witnessed a war that has been going on for many years now, is a country founded by the French after the Turkish War of Independence in the early 20th century, and the border between Turkey and Syria was drawn up during the French mandala. One of the characteristics of this border line—which is also valid for most of the newly-founded Middle-Eastern and African nation-states—is that historic and ethnic continuities have not been calculated, and that it was drawn up as if with a ruler. This characteristic has revealed various border fancies in terms of the states with political borders and the people or groups living on the border line. Undoubtedly, one of the areas in which political borders are visualized differently by the state and the border people is the cross-border trade. In this study, the economic action, defined from the perspective of the state as 'smuggling' between Nusaybin, a county in Mardin and the city of Qamishli in Syria, which are situated oppositely in the Turkish-Syrian border region, has been handled. The conversion of land, which has a traditional use value, into a territory for modern states, can problematize a 'natural' economic activity by making it 'illegal'.

INVESTIGATIONS ON BALLISTIC METHOD APPLICATION FOR SELF-STRENGTHENING 35 MM GUN BARRELS

The paper includes an analysis of a concept for increasing the service life of 35 mm gun barrels by technological process of self-strengthening. A process of barrel self-strengthening that uses a ballistic method based on technological firings with special ammunition of increased propelling charge is considered. In effect of analytical - numerical studies it was stated that a self-strengthening effect is strictly limited to the cartridge chamber and has a local character i.e. the plastic deformation of barrel’s material includes not more than 30% of barrel wall thickness. The received results indicate that efficiency of self-strengthening provided by the ballistic method is low and in cases of deploying materials with high strength characteristics in barrels it could not bring any benefits at all.

Inverse heat conduction modeling to predict heat flux in a hollow cylindrical tube having irregular cross-sections

This study presents the development process of a three-dimensional analysis model for conducting inverse heat transfer analysis of gun barrels with varying cross-sections. In addition, it predicts heat flux in real barrels by using temperature measurements from gun firing experiments. Type-A and type-B guns are used for the experiments. Temperature is measured by independent firings of 1, 5, 10, 20, and 30 rounds for a type-A gun and by consecutive firings of 1, 5, and 7 rounds for a type-B gun. The surface temperature measurements of the gun barrels thus obtained are utilized to predict heat flux, and the effect of firing is examined by comparing the heat flux between different points on the barrels. From the heat flux results for the two types of guns, it is clear that the heat flux increases with increasing number of rounds. On the other hand, the mean value of heat flux shows that the heat flux tends to decrease toward the end of the barrel.

Effect of Yield Criterion on Stress Distribution and Maximum Safe Pressure for an Autofrettaged Gun Barrel

<p>World artillery in the present scenario is changing its role from defensive to aggressive nature and is attempting to achieve higher penetration into enemy targets. Even for an autofrettaged gun barrel, higher ranges requirement leads to higher barrel weight and its associated demerits. The design of gun barrel is based on the choice of yield criteria. Tresca yield criterion provides conservative design for a ductile barrel material. On the other hand, more accurate von Mises criterion presents complexity. The two criteria to evaluate various parameters required for design of an autofrettaged gun barrel are compared. The methodology for evaluation of maximum safe pressure, based on von Mises criterion, for an autofrettaged gun barrel is also included in the paper. Based on case study included in the article, for an autofrettaged gun barrel or pressure vessel with uniform thickness, a theoretical weight reduction of approximately 16 per cent is feasible with von Mises criterion as compared to Tresca criterion.</p>

The Effects of the Material's Exact Yield Point and Its Plastic Properties on the Safe Maximum Pressure of Gun Barrels

The design of a gun barrel aims at maximizing its firing power, determined by its safe maximum pressure (SMP)—the maximal allowed firing pressure—which is considerably enhanced by inducing a favorable residual stress field through the barrel's wall commonly by the autofrettage process. Presently, there are two distinct processes: hydrostatic and swage autofrettage. In both processes, the barrel's material is fully or partially plastically deformed. Recently, a 3D computer code has been developed, which finally enables a realistic simulation of both swage and hydraulic autofrettage processes, using the experimentally measured stress–strain curve and incorporating the Bauschinger effect. This code enables a detailed analysis of all the factors relating to the final SMP of a barrel and can be used to establish the optimal process for any gun-barrel design. A major outcome of this analysis was the fact that the SMP of an autofrettaged barrel is dictated by the detailed plastic characteristics on the barrel's material. The main five plastic parameters of the material that have been identified are: the exact (zero offset) value of the yield stress, the universal plastic curve in both tension and compression, the Bauschinger effect factor (BEF) curve, and the elastic–plastic transition range (EPTR). A detailed comparison between three similar barrel materials points to the fact that the major parameter determining the barrel's SMP is the yield stress of the material and that the best way to determine it is by the newly developed “zero offset” method. All other four parameters are found to have a greater influence on the SMP of a hydraulically autofrettaged barrel than on a swaged one. The simplicity of determining the zero offset yield stress will enable its use in any common elastic and elastoplastic problem instead of the present 0.1% or 0.2% yield stress methods.

Study on Degradation Mechanisms of the Inner Surface of Fire-Arms

This paper presents a study on the behavior of the inner surface of the gun barrel. The service life of the gun barrel of the cylinder is given by the state of their inner surface to which is necessary to know the phenimena leading to its degradation The study aims knowledge and analysis of phenomena taking place inside the cylinder pipe before and after a number of withdrawals and phenomena occurring dragging bullet pipe. Multiple requests at the same time acting corrosion may damage the pipe gun. The amount of wear by oxidation has been studied using the model parameters Quinn correlate the intensity of the action of various oxidation wear.The results showed that the pipes which have been treated electrochemically with a hard chromium layer exhibits a longer life than the untreated ones.

Analysis of Premature Wear-Out of Aircraft Gun Barrel by Applying a Transmission Electron Microscopy (TEM)

Abstract Firing from gun armament generates a wide range of physico-chemical phenomena contributing to the degradation of barrel material, e.g. pressure, high temperature, chemically aggressive character of post-detonation gases and friction of a driving band. In this work the technique of thin foils was used in Transmission Electron Microscopy (TEM) to study the influence of physicochemical phenomena on the material microstructure of aircraft gun barrel. A mechanism and reason of premature wear-out of the barrel under consideration was also outlined by utilising light microscopy and hardness measurements.

Casting and Casting Processes

The casting process was discovered probably around 3500 BC in Mesopotamia. Casting is unique manufacturing processes for a variety of reasons. Perhaps the most obvious is the array of molding and casting processes available that are capable of producing complex components in any metal, ranging in weight from less than an ounce to single parts weighing several hundred tons. Foundry processes are available and in use that are economically viable for producing a single prototype part, while others achieve their economies in creating millions of the same part. Virtually any metal that can be melted can and is being cast. Many parts and components are made by casting, including automotive components such as carburettors, engine blocks, crankshafts, agricultural and rail road equipments, pipe and pumping fixtures, power tools, gun barrels and large components of hydraulic turbines etc. Since 1950, partially automated casting processes have been developed for production lines.It is estimated that castings are used in 90% or more of all manufactured goods and in all capital goods machinery used in manufacturing. The diversity in the end use of metal castings is a direct result of the many functional advantages and economic benefits that castings offer compared to other metal forming methods. The beneficial characteristics of a cast component are directly attributable to the inherent versatility of the casting process.

The uncertainty propagation analysis of the projectile-barrel coupling problem

Abstract Based on the model which couples the projectile and gun barrel during an interior ballistic cycle, the uncertainty propagation analysis of the model is presented caused by the uncertainty of the input parameters. The Bootstrap method is employed to calculate the statistical moments (i.e. the mean, variance, skewness coefficient and kurtosis coefficient) of the parameters of the projectile. Meanwhile, the maximum entropy method is used to estimate the probability density function (PDF) and the cumulative density function (CDF), the interval of the parameters of the projectile are also given. Moreover, the results obtained are compared to the results calculated by Monte Carlo (MC) method to verify the effectiveness of the presented method. Finally, the rule and the uncertainty propagation model of the projectile-barrel coupling system are given with the variation of the uncertainties of the input parameters.

Development of ergonomic gun barrel cleaning method: Automation and its advantages

AbstractThe aims of this study were to assess postural risks associated with the current gun barrel cleaning method and to develop an ergonomic gun barrel cleaning method that could reduce such risks. The inner surfaces of gun barrels should be cleaned after use to maintain their firing function. The current method of cleaning gun barrels requires multiple soldiers to push and pull a long cleaning pole for 1–3 hr. Such motions require both hands to be raised to shoulder height. The current manual method and a newly designed automated method were compared in terms of safety and effectiveness. Postural risk assessments were performed using OWAS, RULA, and REBA. Results: The manual cleaning method involves the highest postural risk level (Action Category/Level 4), requiring immediate intervention, and exposes multiple soldiers to life‐threatening situations for a longer time during wartime. The postural risk associated with using the automated cleaning system was much lower (Action Category/Level 2). Once loaded into the gun barrel by a single soldier, the automated system takes approximately 20 min to complete cleaning. The automated cleaning method reduces musculoskeletal disorder risks associated with cleaning gun barrels and increases military power. The automated gun barrel cleaning method is an ergonomic solution that can be used for cleaning gun barrels within a short time without exposing soldiers to postural risks.

Verbal Cues and Attentional Focus: A Simulated Target-Shooting Experiment

Performance benefits exist for an external focus of attention compared with an internal focus of attention for performance and learning (Wulf, 2013). It is unknown, however, if varying the number of verbal cues affects learning and performance. Focus of attention and the number of verbal cues were manipulated during a simulated handgun-shooting task. For the internal focus conditions, participants were told to focus on their hand, arm, and wrist, whereas the external focus instructions were to focus on the gun, gun barrel, and gun stock. To manipulate the number of verbal cues, participants received instruction to focus on a single verbal cue or multiple verbal cues. Shooting performance was assessed at baseline, acquisition, and at two separate retention phases (immediate, delayed) that included transfer tests. Participants completed the NASA—Task Load Index to assess workload following all trials. Participants who received one verbal cue performed significantly better during immediate retention than those who received three verbal cues. Participants who used external focus of attention instructions had higher performance and reported less workload at delayed retention compared to those who used internal focus instructions. This research provides further support for the benefits of an external focus and highlights the importance of minimizing the number of verbal cues.

SPINS-IND: Pellet injector for fuelling of magnetically confined fusion systems.

Using a Gifford-McMahon cycle cryocooler based refrigeration system, a single barrel hydrogen pellet injection (SPINS-IND) system is indigenously developed at Institute for Plasma Research, India. The injector is based on a pipe gun concept, where a pellet formed in situ in the gun barrel is accelerated to high speed using high pressure light propellant gas. The pellet size is decided by considering the Greenwald density limit and its speed is decided by considering a neutral gas shielding model based scaling law. The pellet shape is cylindrical of dimension (1.6 mm ℓ × 1.8 mm φ). For pellet ejection and acceleration, a fast opening valve of short opening duration is installed at the breech of the barrel. A three-stage differential pumping system is used to restrict the flow of the propellant gas into the plasma vacuum vessel. Diagnostic systems such as light gate and fast imaging camera (240 000 frames/s) are employed to measure the pellet speed and size, respectively. A trigger circuit and a programmable logic controller based integrated control system developed on LabVIEW enables to control the pellet injector remotely. Using helium as a propellant gas, the pellet speed is varied in the range 650 m/s-800 m/s. The reliability of pellet formation and ejection is found to be more than 95%. This paper describes the details of SPINS-IND and its test results.

Identification of polymers and organic gunshot residue in evidence from 3D-printed firearms using DART-mass spectrometry: A feasibility study

Rapid advances in 3D-printing technology have created an emerging class of firearms. As the movement to self-manufacture firearms with 3D-printing grows, it is reasonable to assume that they will be increasingly used in crimes. Here, we test-fired gun barrels made with acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polyethylene terephthalate (PETG), chlorinated polyethylene (CPE), and nylon. The resulting cartridge cases, bullets, and gunshot residue (GSR) were examined by direct analysis in real time – mass spectrometry (DART-MS). High-resolution mass spectra detected polymer from the gun barrel on bullets and cartridge casings for a 0.38 special caliber gun and, to a lesser extent, for a 0.22 caliber 3D-printed gun. Particles of plastic were identified in some GSR samples collected from clothing used as a backstop for test-fires. DART-MS also readily detected signature organic GSR compounds, including methyl centralite, ethyl centralite, diphenylamine, and nitrocellulose, on recovered bullets, cartridge cases, and in extracts of SEM stubs used to collect GSR from the clothing. Overall, this study demonstrates that analysis of firearm trace evidence using DART-MS deserves more attention, and that the technique may be particularly useful for investigating crimes involving 3D-printed guns.

A review on the gun barrel vibrations and control for a main battle tank

Abstract Achieving high hitting accuracy for a main battle tank is challenging while the tank is on the move. This can be reached by proper design of a weapon control and gun system. In order to design an effective gun system while the tank is moving, better understanding of the dynamic behavior of the gun system is required. In this study, the dynamic behaviour of a gun system is discussed in this respect. Both experimental and numerical applications for the determination of the dynamic behaviour of a tank gun system are investigated. Methods such as the use of muzzle reference system (MRS) and vibration absorbers, and active vibration control technology for the control and the reduction of the muzzle tip deflections are also reviewed. For the existing gun systems without making substantial modifications, MRS could be useful in controlling the deflections of gun barrels with estimation/prediction algorithms. The vibration levels could be cut into half by the use of optimised vibration absorbers for an existing gun. A new gun system with a longer barrel can be as accurate as the one with a short barrel with the appropriate structural modifications.

Swage and hydraulic autofrettage impact on fracture endurance and fatigue life of an internally cracked smooth gun barrel Part I – The effect of overstraining

Three dimensional Mode I Stress Intensity Factor (SIF) distributions along the front of a single inner radial semi elliptical crack emanating from the bore of an autofrettaged smooth gun barrel are evaluated. The barrel is assumed to have been overstrained by either the Swage or the Hydraulic autofrettage processes. The 3-D analysis is performed using the finite element (FE) method employing singular elements along the crack front. Novel realistic overstrain residual stress fields, incorporating the Bauschinger effect, for the two autofrettage processes are applied to the barrel. For comparison reasons Hill's (Hill, 1950) residual stress field (RSF) is also applied. The RSFs for Swage and Hydraulic autofrettage as well as Hill's solution are simulated in the FE analysis using equivalent temperature fields. Values for KIA - the SIF resulting from the compressive residual stresses induced by autofrettage are evaluated for a typical barrel of radii ratio R0/Ri=2, a wide range of crack depth to wall-thickness ratios (a/t=0.005–0.1), various crack ellipticities (a/c=0.2–1.0), and five levels of Swage, Hydraulic and Hill's autofrettage (ε=40%, 60%, 70%, 80%, and 100%). In total, 375 different 3-D crack cases are analyzed. A detailed study of the influence of the above parameters on the prevailing SIF is conducted. The results clearly indicate the favorable effect of all three types of autofrettage in reducing the prevailing effective stress intensity factor and thus delaying crack initiation, slowing down crack growth rate, and substantially prolonging the total fatigue life of the barrel. However, the favorable effect of autofrettage is type-dependent. The realistic Swage and Hydraulic autofrettage RSFs are found to differ considerably from each other. The beneficial effect of Swage autofrettage is found to be considerably superior to that resulting from Hydraulic autofrettage. Hill's autofrettage is far from being realistic as it overestimates the RSF magnitude and thus exaggerates the beneficial effect of autofrettage. Finally, the results highlight the importance of properly accounting for the Bauschinger effect including re-yielding, as well as the significance of the three dimensional analysis herein performed.