Gun Barrel Research Articles

Thrifty Science: Making the Most of Materials in the History of Experiment by Simon Werrett

Reviewed by: Thrifty Science: Making the Most of Materials in the History of Experiment by Simon Werrett Lachlan Fleetwood (bio) Thrifty Science: Making the Most of Materials in the History of Experiment. By Simon Werrett. Chicago: The University of Chicago Press, 2019. Pp. 304. Hardcover $45. Thrifty Science takes the reader on a fascinating and novel tour of early modern science, wending its way through homes and gardens, auction houses, and instrument shops. In unpacking notions of thrift—in their many guises of maintenance, repair, repurposing, reuse, and exchange—Werrett asks how early modern scientific practitioners adopted and adapted the materials for their experiments. Here "thrift was as much moral as material" (p. 21) and reflected the way "experimenters were keen to explore a variety of uses of mundane material objects that were ready to hand in order to learn about nature" (p. 16). The book is foremost a contribution to the growing literature on the material culture and practice of science, with an analysis rooted in notions of circulation. At the same time, it speaks eloquently to recent work on the early modern home, convincingly locating many of the thrifty practices of science in ideas of oeconomy and the management of the household. Canonical figures like Robert Boyle, Robert Hooke, and Isaac Newton thus naturally appear, but the focus on the home also opens up a more diverse cast of men and women, including family members and domestic servants, as participants in early modern science. Werrett takes the classic question of "what is a scientific instrument" and reverses it, instead suggesting that it "might be more appropriate to ask what was not one" (p. 82). For the early modern English experimenters Thrifty Science traces, the answer seems to be very little. Indeed, while acknowledging the place of specific experimental apparatus (like the air pump) in this earlier period, Werrett argues that such devices were more the province of the nineteenth century. Instead, all manner of household items, including "kitchens, bedchambers, pokers, gun barrels, wineglasses, and stockings were 'made use of' or 'put into the service of' experiment" (p. 7). A particularly delightful example in this regard is Robert Symmer's use of his own silk stockings to develop a theory of electricity. The book deals primarily with the seventeenth and eighteenth centuries, though the final chapter extends into the nineteenth century. In this period, Werrett posits a transformation from "thrifty science" to "economic science," which entailed a greater focus on specialized, single-use instruments and "encouraged a different approach to material things, presenting them as complete rather than open-ended, as commodities to be consumed rather than continuously reworked" (p. 167). This was coupled with an increasingly rigid (and deliberately gendered) separation between the home and laboratory. Werrett concludes by deftly connecting these [End Page 1102] concerns to twentieth-century "Big Science," and reflecting on their implications for the present. Here "modern environmental practices" might be seen as "a re-recognition of thrifty practices that have been going on in one form or another for centuries," albeit with different motivations (p. 2). As such, re-engaging with oeconomic practices, and seeing material things as "incomplete" and "open-ended" may "offer ways to think about how we might be thrifty in the future" (p. 2). Thrifty Science's geographical focus is firmly on England (with occasional forays into North America), a scope that is freely acknowledged as "rather narrow" (p. 11). Werrett nevertheless rightly takes the time to collapse the received notion that the metropole was always the center of "the new" and of innovation—in contrast to those in the colonies who had to "make do" and find substitutes—as "a (mostly Victorian) fiction" (p. 12). However, this insistence on England is at times limiting, especially given that new imperial histories have shown that metropoles like London cannot be so easily separated from their empires. More about the thrifty use of materials between say England, Asia, and the Caribbean would thus have been welcome. Ultimately though, this amounts less to criticism of the present work than it does an opportunity for expanding its central questions into new contexts. The variety and depth of sources on display is prodigious, and...

Design and test bench operation results of a solid hydrogen pellet injector developed for SST-1 tokamak

A single barrel pellet injection system is developed for pellet injection related studies targeting SST-1 tokamak plasma. Conventional pipe gun concept is adopted for designing the injector. The hydrogen ice is formed in-situ in the gun barrel, and a high pressure light propellant gas is used to dislocate the pellet from the freezing zone and accelerate it to higher speed. This system uses a cryogen free, closed loop compact cryocooler, which provides ease of handling and operational reliability to the pellet freezing process. Pellet parameters such as size and speed are considered by using the density limit and neutral gas shielding (NGS) model based calculations, respectively. The designed size and speed (Vp) of the pellet is fixed at (1.6 mm length [ℓ] × 1.8 mm diameter [φ]) and Vp < 800 m/s, respectively. A programmable logic controller (PLC) based control system and a graphical user interface (GUI) is developed and installed to operate the injector remotely. This paper presents the design and test results of the injector such as pellet freezing capability, effect of temperature gradient along the barrel on pellet formation process and its speed control with propellant pressure.

Recognition of distribution of the center for diffusion of snares as a result of heating the stroke of the equipment during the fire of the fire problem

The article gives a brief analysis of the use of artillery in the course of an anti-Eurasian operation in the east of Ukraine. Artillery units were involved in a significant number of fire missions with a large expenditure of ammunition. Most artillery missions are performed to defeat unobservable targets, the destruction and suppression of which, as a rule, requires a large amount of ammunition and considerable fire time, which leads to the heating of gun barrels. As a result of the heating of the barrels, the initial velocity of the projectiles changes, the scattering of projectiles from the point of aiming at a range that does not allow for which may lead to a decrease in the effectiveness of the fire, and in some cases to the non-fulfillment of the fire task. The artillery units and subunits received new and modernized weapons, for which there are no tables for determining the deviations of the initial velocity of shells from the tabulated value with the help of ABS-1 and the Table of Accounting, mixing the center of scatter of projectiles as a result of the heating of the barrel. Taking into account the combat experience of the use of artillery units and subunits, and on the basis of the conclusions drawn in the Rules of shooting and fire control of ground artillery of 2018 (PSiUO NA), amendments to the section on ballistic training for the need to take into account the corrections for the heating of gun barrels are missing, but there is no procedure for determining them.The article details the procedure for the work of the division's officials in organizing settlements and recording corrections for the heating of gun barrels during the preparation of installations for shooting and during the execution of fire missions. The example of the 152 mm cannon 2A36 divisions presents the procedure for using tables and formulas in the calculations, and also shows the magnitude of possible corrections for range as a result of the heating of the barrels and the displacement of the center of the projectile scattering from the aiming point. The need to provide artillery units with tables for determining the total deviation of the initial speed from the tabulated value using ABS-1 and tables for determining the number of conditional shots for different charge numbers, initial speed deviations and the ballistic coefficient for all artillery pieces that are in service with artillery units of the Armed Forces forces of Ukraine.

Estimation of the Time-Varying High-Intensity Heat Flux for a Two-Layer Hollow Cylinder

Gun barrels are subjected to time-varying high-intensity heat flux under multiple firing, which may damage the material and limit the overall performance of the gun. In order to monitor the thermal state of a gun barrel, an inverse method coupling the finite difference method with the sequential function specification method was developed to estimate the unknown time-varying heat flux imposed on the inner wall of a gun barrel. A two-layer hollow cylindrical tube was assumed with the convection heat transfer boundary condition on the outer wall of the tube. A direct heat transfer model was developed, and was used to estimate the temporal distribution of boundary heat flux in approximately real time based on the measured transient temperature at some positions on the outer wall of the gun barrel. Numerical tests were performed to verify the effectiveness and reliability of this method by investigating the influence of temperature measurement noises and future time step selection. The results show that the proposed method has high precision and efficiency in extracting the time-varying heat flux under one-shot and three-shot firing conditions. When there is a measurement noise, this method has good anti-illness characteristics and can achieve better results by appropriately selecting the value of a future time step.

The detrimental effect of autofrettage on externally cracked modern tank gun barrels

Overstraining gun tubes has a twofold advantage. First, it enables the increase of the Safe Maximum Pressure (SMP) in the tube, resulting in a higher muzzle velocity which extends the gun's range and its projectile kinetic energy. Second, it reduces the tube's susceptibility to internal cracking which prolongs its fatigue life. Unfortunately, autofrettage also bears an inherent detrimental effect as it considerably increases the tensile hoop stress at the outer portion of the barrel's wall, which enhances external cracking of the tube by increasing the prevailing Stress Intensity Factor (SIF). In order to quantify this disadvantageous effect, 3-D Mode I SIFs distributions along the front of a single external radial semi-elliptical crack initiating from the outer surface of an autofrettaged modern gun barrel, overstrained by either the Swage or the Hydraulic autofrettage processes, are evaluated. The analysis is performed by the finite element (FE) method, using singular elements along the crack front. Innovative residual stress fields (RSFs), incorporating the Bauschinger effect for both types of autofrettage are applied to the barrel. Hill's [1] RSF is also applied to the tube for comparison reasons. All three RSFs are incorporated in the FE analysis, using equivalent temperature fields. Values for KIA - the SIF resulting from the tensile residual stresses induced by autofrettage are evaluated for: a typical barrel of radii ratio Ro/Ri = 2, crack depth to wall-thickness ratios (a/t = 0.005–0.1), 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 cases are analyzed. The analysis demonstrates undoubtedly the detrimental effect of all types of autofrettage in increasing the prevailing effective stress intensity factor of external cracks, resulting in crack initiation enhancement and crack growth rate acceleration which considerably shortens the total fatigue life of the barrel. Nonetheless, the detrimental effect is autofrettage-type dependent. Swage and Hydraulic autofrettage RSFs differ substantially from each other. The disadvantageous effect of Swage autofrettage is much greater than that resulting from Hydraulic autofrettage. The results also emphasize the significance of the Bauschinger effect and the importance of the 3-D analysis.

Heat Transfer Calculations in Barrel Cover of 35 mm Naval Armament System Gun

This paper presents the results of numerical simulations of non-stationary heat transfer in a 35 mm anti-air gun barrel cover made of composite materials. The cover protects the gun against weather conditions, including sea water effects, and serves as a protection against mechanical damage. It was assumed that heat coercion in this problem will be the heat condition reached by the material of the barrel with the cover removed, after firing three bursts of 7 shells each, 120 s after opening fire. It was assumed, that in the second 120, the gun crew installs the gun cover and at this point, the heating process begins, followed by cooling of the cover material. The problem of initial and boundary value in the barrel with a cover installed system was solved as a three-dimensional initial and boundary problem. The initial and boundary value model adopted for the coverless barrel and the calculation results for the first burst of seven shells was presented in paper [7]. To obtain the heat condition of the barrel in the second 120, it was necessary to perform calculations for the second and third bursts, and for the barrel cooling processes starting in the second 120. The calculations were performed with a finite element method in the COSMOS/M software [9]. The cover material temperature values obtained during the numerical simulation are well below the temperature of 387K, which could form the upper limit of the composite applicability temperature range.

Research Progress on the Decline of Muzzle Velocity

The tank gun is the main battle weapon of the tank. It is mainly used to destroy and suppress enemy tank armoured vehicles, eliminate living forces and destroy fortifications. However, after repeated use of artillery for a long time, projectile muzzle velocity and maximum pressure will decrease. Shortening distances and increasing the area of projectiles will greatly affect the ability of artillery to carry out combat missions. Taking the gun barrel as the main research object, the main factors that cause the muzzle velocity of the artillery muzzle projectile to be reduced are analyzed. The mechanism of the muzzle velocity is analyzed, and the method for calculating the muzzle velocity decrease is explored, which is of great significance for improving the accuracy of artillery firing. It also provides reference for estimating the life of gun barrels.

포신 수명 증대를 위한 최적 강선 형상 설계

포신 수명 증대를 위한 최적 강선 형상 설계

Dynamic analysis of gun barrel vibrations due to effect of an unbalanced projectile considering 2-D transverse displacements of barrel tip using a 3-D element technique

Abstract In this paper, dynamic analysis of two different weapon systems (35 mm Anti-Aircraft Barrel (AAB) and 120 mm Grooved Tank Barrel (GTB)) under the effect of statically unbalanced projectile has been performed with a new 12 DOF 3-D element technique using Finite Element Method (FEM). The muzzle deviations, which negatively affect the barrel shooting accuracy at firing, are calculated in a time dependent manner using Newmark β algorithm with high accuracy at both axes (y and z) considering the Coriolis centripedal and centrifugal forces. The effect of such fundamental physical parameters as shift from rotating center and angular velocity belonging to the unbalanced projectile on barrel dynamics are analyzed with this new and affective FEM. As a result, it was found out that 1% of a millimeter shift from projectile belonging to a weapon system leads to excessive vibration on both axes and compromises the shooting accuracy of the barrel.

Protective trivalent Cr-based electrochemical coatings for gun barrels

Conventional Cr as a protective coating on gun barrels is electro-deposited from toxic hexavalent chromium electrolyte, which can be susceptible to cracking and tends to spall off. Herein, environment friendly trivalent Cr bath was utilized to electrodeposit chromium based composite coatings on armour steel with the incorporation of 3 mol% yttria stabilised zirconia (3YSZ) and carbon nano tubes (CNT). Higher dislocation density (17 × 1015 m−2), yield strength (4.6 GPa), calculated using Taylor's model, and reduced plasticity index (0.29) resulted in an enhanced hardness (∼25 GPa) and elastic modulus (∼206 GPa) for the synergistically incorporated YSZ and CNT in Cr matrix when compared to the Cr, Cr-YSZ and Cr-CNT coatings (using micro and nano-indentation techniques). Moreover, the fretting wear testing also elicited Cr-YSZ-CNT as most adroit coating having enhanced wear resistance (wear rate ∼3.7 × 10−5 mm3/Nm) due to the efficient presence of compressive stress (−918 MPa) and fine crystallite size (11 nm). The reduction in Hertzian contact diameter, from 32 μm for Cr to 27 μm for Cr-YSZ-CNT coating, results in a decreased tribological interaction between the counter body and coating material during the wear test. The mechanism involved in Cr-YSZ-CNT coating, grafted significantly with the mechanical and tribological performance, was attributed to toughening by YSZ nanoparticles that strengthen Cr matrix and impart higher resistance to crack-propagation during fretting wear. While the lubrication and bridging phenomenon of CNTs can potentially seal-up the initiation and propagation of cracks and pores within the matrix, thereby reducing the damage due to the wear. Thus, the dexterous mechanical and tribological performance of Cr-YSZ-CNT coating over Cr, Cr-YSZ and Cr-CNT coatings, makes it suitable composite material for gun barrel protection.

Application of Pythagorean fuzzy AHP and VIKOR methods in occupational health and safety risk assessment: the case of a gun and rifle barrel external surface oxidation and colouring unit

The field of occupational health and safety (OHS) focuses on reducing occupational accidents to an acceptable level. OHS covers systematic efforts aimed at providing employee health, safety and welfare in the workplace. This study proposes a new approach for risk assessment in the field of OHS. It integrates the Pythagorean fuzzy analytic hierarchy process (PFAHP) and fuzzy VlseKriterijumska Optimizacija I Kompromisno Resenje (FVIKOR) into a risk assessment process. The PFAHP is used in weighting the risk parameters. FVIKOR is then applied to prioritize the hazards. To demonstrate the applicability and validity of the proposed approach, a case study of a barrel external surface oxidation and colouring unit of a gun and rifle production facility is performed. A comparison is also provided between the proposed approach and an intuitionistic fuzzy sets-based approach. The proposed approach is found to produce reliable outcomes that better represent the vagueness of the decision-making process.

Numerical evaluation of an autofrettaged thick-walled cylinder under dynamically applied axially non-uniform internal service pressure distribution

Abstract A dynamical moving pressure structural numerical calculation model using the internal ballistics calculation pressure-time results was constituted and the vicinity of the internal ballistics and quasi-internal ballistics structural model was checked. The Von Mises stresses obtained by the dynamical structural numerical model calculations and the Von Mises stresses calculated from the shot test strain measurements were compared. The difference for the worse case was 20% and for the best case was 0.1%. Furthermore, the model gave better agreement for the higher charge masses. The numerical structural quasi-internal ballistics computation model created was verified for the top charge mass which represents the highest stress condition and used in a gun barrel design.

A late medieval or early modern light gun barrel from the Castle Museum in Malbork\u2014typology, technology of manufacture and identification of the smelting process

The paper discusses a gun barrel of a possibly late 15th-early 16th c. date from the collection of the Castle Museum in Malbork (Marienburg), Poland (MZM/468/MT). The barrel was originally part of a hand-held gun (a hackbut?) and was later converted into a light cannon. The barrel was made from unevenly carburised soft steel (c. 0.1–0.2% C). Both metallographic examinations and the analysis of slag inclusions with the use of multivariate statistics suggest that the metal in the barrel was manufactured using the direct (bloomery) smelting process.

Effects of Tank Gun Structural Components on the First Shot Hit Probability

Fire power for a main battle tank is one of the most important performance parameters like survivability and mobility. Fire power effectiveness is directly related to the first shot hit probability, performance of main gun, second armament, gun and turret drive system, fire control system, automatic target tracker, commander and gunner sight etc. First shot hit probability (a measure of cumulative effects of errors) is affected by the variations of the projectile parameters, the main gun structure uncertainties, fire control system errors, interaction between the projectile and the gun barrel and the unpredictable environmental changes. These errors and variations can be eliminated or minimised by understanding and simulating the firing event properly, manufacturing the related parts in high precision, using advanced fire control algorithms, and accurate sensors. In this review study, the effects of main gun structural components on the first shot hit probability are investigated taking into account all of the associated error sources. In order for a main battle tank to have both high and repetitive first shot hit probability under all battlefield conditions the gun structure should respond in a similar manner in successive firings without causing any abrupt change in performance. In this study, first the dynamic behaviour of gun/projectile system is discussed and then the design recommendations for the main gun components such as bearings, gun barrel, recoil system etc. to achieve higher first shot hit probability are reviewed.

Strain-based health monitoring and remaining life prediction of large caliber gun barrel

When a large caliber rifled gun fires, wear and fatigue damage the gun barrel and lead to the end of its useful life. It is important to understand the gun barrel condition during its service time and to predict the remaining useful life. In this paper, three traditional life prediction methods, including heat-based, dimension-based and velocity-based method, are summarized and proved to be insufficient for predicting the remaining useful life. A novel strain-based approach to life prediction of gun barrel is presented and analyzed theoretically, in which the strain of the outside surface of gun barrel is selected as a health index of the gun barrel. A large number of laboratory experiments on engraving small caliber projectiles have been carried out to verify the reasonability and feasibility of this strain-based method. Self-made copper and brass jacketed projectiles were pushed through a short gun barrel section under quasi-static and dynamic loading. The hoop and axial strains were measured using strain gauges and stored for analysis. Experimental results are listed as follows. (1) The measured strains do reflect the interaction between projectile and gun barrel under different test conditions. (2) Material property of jacket and diameter of projectile have influence on the external strains. (3) The jacket undergoes friction and plastic deformation during the engraving process. Effects of strain rate and thermal softening play critical roles in affecting the projectile and gun barrel interaction. This finding helps to explain that higher strains at low charges and lower strains at high charges occur to a 155 mm gun during firing practice.

Gun Barrel Refurbishing Using a Shrink-Fitted Autofrettaged Liner

During the firing of guns, the barrel undergoes two major damaging processes: wear of its inner surface and internal cracking. Barrel's are condemned based on either the increase of their internal diameter due to wear or the severity of their internal cracking. The cost of replacing such a damaged gun barrel runs in the tenth of thousands of U.S.$. Therefore, cost effective methods are sought for restoring such gun barrels. In the present analysis, a new method is proposed for refurbishing vintage gun barrels by machining their inner damaged layer and replacing it by an intact, autofrettaged, shrink-fit liner that will restore the barrel to its original performance. The design of the shrink-fitted liner is based on two design principles. First, the von-Mises residual stress distribution through the thickness of the barrel at each of its cross sections along the inserted liner should be at least equal in magnitude to von Mises stress, which prevailed in the original barrel. Second, once the maximum pressure is applied to the compound barrel, the von-Mises stresses at the inner surfaces of the liner machined barrel should be equal to their respective yield stresses. The preliminary results demonstrate the ability of this process to mend such barrels and bringing them back to their initial safe maximum pressure (SMP) and their intact conditions, rather than condemn them. Furthermore, from the authors' experience, based on a preliminary rough estimate, such an alternative seems to be cost effective.

Dynamic response for shock loadings and stress analysis of a trajectory correcting fuse based on fuse–projectile–barrel coupling

This paper creates a fuse–projectile–barrel coupling model and conducts an implicit–explicit sequential finite element dynamic simulation to analyze the response of the components in ammunition to shock loadings during the whole launch process accurately. The engraving process continues at 3.05 ms and leads to the acceleration fluctuation of the fuse bearings. The deflection of the gun barrel due to gravity at 52 degrees quadrant elevation (QE) is acquired. Then the displacement and velocity of the projectile are obtained to verify the gun tube deflection. The bearing axial and radial acceleration in the fuse are depicted. The results indicate that the axial acceleration imposed on the bearings during launch is a major loading, and base pressure and pressure dissipation result in shock loadings on the bearings. The accelerated spin and collision of the projectile with the barrel produce centrifugal inertia force and gyroscopic coupling, which influence the radial acceleration. In addition to this, a calculation method is proposed to work out the maximal contact stress of the bearing’s components. The method is combined with the bearings’ components maximal acceleration from simulation. The results of the research prove that the calculation method is correct and credible. The research conclusions provide some reference for the structural design of a trajectory correcting fuse.

The Enfield Lock Barrel Mill of 1815 and Moves to Replace Musket Barrel Grinding by Turning c1780 to c1840

In 1841 Henry Wilkinson in his book Engines of War and William Greener in The Science of Gunnery describe a range of methods then in use for shaping the outside of gun barrels after the barrel forging process, ranging from manual off-hand grinding to the use of precision machines. In the same year G. & J. Rennie published the design of their state-of-the-art lathe that was capable of turning complex and dished barrel forms. This built upon the earlier work of both Henry Nock and John Jones. In the early years of the 19th century both Britain, at Enfield and other locations, and the USA, at Harpers Ferry and Springfield, began to introduce barrel-turning technology. This paper uses measurements taken from a significant number of military barrels made by several makers, and also newly exposed information about Henry Nock and the Enfield Factory of 1815, to understand better the technologies that were applied to military flintlock barrel finishing from the 1780s to the 1840s, and particularly during the major wars of 1793–1815, when high output was paramount. Measurements both of barrel form and out-of-roundness are presented. These allow the interpretation of the techniques being used by different makers at different locations, and raise questions about the purpose and achievement of the complex dished barrel forms found on British military flintlock muskets. This approach also allows us to better describe the earliest factory on the Enfield site, one of the most significant sites in the wider history of UK manufacturing.

Experimental and numerical analysis of thermo-chemical erosion in gun steel

Various factors of thermo-chemical erosion process in gun steel were analysed. The factors are mainly related to the thermal load of gun barrel inside surface, characteristics of barrel surface and chemical interactions between propellant combustion products and barrel surface. The experimental simulation of conditions in gun barrel was carried out by vented vessel firings in the device based on modification of 37 mm M39 gun. The nozzle mass loss during firing was the measure of gun steel erosion. The main thermal factor of erosion is maximum nozzle inner surface temperature. This temperature was determined experimentally by micro thermocouples measurements at specified distance away from the inner surface and by numerical analysis of the inverse heat conduction problem. Modelling of two-phase flow of propellant combustion products and unburned propellant grains in the vented vessel and heat transfer to the nozzle were conducted using developed 1-D interior ballistic code and CFD simulation in FLUENT. Influence of different propellants, TiO2/wax wear reducing liner and tungsten-disulfide nanoparticles layer on nozzle erosion was analysed. Good agreement between experimental and computational results was achieved.

Design Of Sabot &Catcher System OfSingle Stage Gas Gun For Bird And Hailstone Impact Test

Sabots are used in gas guns to hold bird and hail projectiles in aerospace component test. Sabots used for bird and hail projectiles are classified by their construction into split and single piece sabot. Design procedure for split and single piece sabot are highly empirical and depends on the type of projectile. Design methodology is developed for split sabot and the relation between sabot dimensions, geometric features, density of the sabot material, number of sabot pieces, velocity of sabot at the gun exit and the radial travel distance during the travel between gas gun barrel exit and test article are calculated. This methodology is validated using explicit finite element simulation of an axisymmetric model of sabot and projectile exiting the gas gun barrel. Design methodology of the single piece sabot is different from split sabot and depends more on the sabot material properties. Analytical formulation for single piece sabot design is discussed. Three dimensional explicit finite element simulations are carried out to validate the design procedure and the relation between the sabot stopping distance, sabot material and the design parameters of the sabot catcher system are discussed.