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Comprehensive Erosion Model For The 120 Mm M256 M829a2 Gun System
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Book Synopsis Comprehensive Erosion Model for the 120-MM M256/M829A2 Gun System by :
Download or read book Comprehensive Erosion Model for the 120-MM M256/M829A2 Gun System written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most 120-mm M256 guns firing the M829 round as their "honest" kinetic energy round have been condemned because of fatigue. Despite this fact, it is still important to determine the erosion life of the M829 round, since M256 guns that have fired the most recent kinetic energy rounds (M829A1, M829A2) rely on the M829 round for baseline dispersion testing of that gun. Today this generally results in M256 guns that having an equal mix of M829 and M829A2 rounds, thus necessitating the consideration of M829 round effects for any erosion analysis. Variability exists for M256 guns with M829 rounds depending on round count, round type, round-conditioning temperature, and their order. Distinctive erosion patterns and mechanisms are emerging as our gun erosion database increases for in-service and out-of-service 120-mm M256 tubes with M829 rounds. Our M256/M829 gun system erosion model-with its interior ballistics, thermochemistry, and boundary layer components-is constantly being guided and refined by the erosion and materials analysis data from fired gun tubes. A recent refinement includes improvement of the gun steel subsurface exposure model due to high quality, difficult to obtain data from in-service M256 tubes. Other recent refinements to the boundary layer heat transfer model are based on thermal data from M256 tubes. These refinements include the improvement/incorporation of case gas cooling effects, turbulent gas mixing/heating effects, and a very minor contribution from forcing cone-induced vena contracta cooling effects. These latter refinements are calibrated away from crack walls by positional thermal wall repacking depth, thermal wall transformation depth, and thermocouple data.
Book Synopsis Erosion Modeling of the 120-MM M256/M829A2 Gun System by :
Download or read book Erosion Modeling of the 120-MM M256/M829A2 Gun System written by and published by . This book was released on 1997 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Benet Laboratories/Software and Engineering Associates, Inc. (SEA) gun barrel erosion modeling and design code predicts wall degradation due to transformations, chemical reactions, and cracking coupled with pure mechanical erosion for the 120-man M256/MS29A2 gun system for ambient temperature-conditioned rounds. The A723 steel and 0.005-inch high contraction (HC) chromium plated/A723 steel wall materials are evaluated for erosion. This complex computer analysis is based on rigorously evaluated scientific theory that has been validated in the rocket community over the last forty years. Our gun erosion analysis includes the standard interior ballistics gun code (XNOVAKTC), the standard nonideal gas-wall thermochemical rocket code modified for guns (CCET). the standard mass addition boundary layer rocket code modified for guns (MABL), and the standard wall material ablation conduction erosion rocket code modified for guns (MACE). In addition, bore subsurface metallographic analysis and projectile-bore finite element analysis (ABAQUS) are considered. Our overall analysis provides wall material erosion predictions and comparisons of ablation, conduction, and erosion profiles as a function of time, travel (customer-selected 27. 61, 86, 130, and 201 inches from the rear face of the tube), and number of rounds to barrel condemnation. The 120-mm M256/M829A2 gun system prediction, with significant numbers of M829A2 rounds, agrees well with the wear and erosion pattern of retired M256 gun barrels.
Book Synopsis Shot-By-Shot Erosion Modeling of Retired 120mm M256 Gun Tube #1988 by :
Download or read book Shot-By-Shot Erosion Modeling of Retired 120mm M256 Gun Tube #1988 written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As our gun erosion database increases for in-service and out-of-service 120-mm M256 tubes with M829Ax series rounds, distinct erosion patterns and mechanisms are emerging. Variability exists for M256 guns with M829Ax series rounds depending on round count, round type, round-conditioning temperature, and their order. Our M256/M829Ax gun system erosion model - with its interior ballistics, thermochemistry, and boundary layer components - is constantly being guided and refined by the erosion and materials analysis data from fired gun tubes. A recent refinement includes the improvement of the gun steel subsurface exposure model due to high quality, difficult to obtain data from in-service M256 tubes. Other recent refinements to the boundary layer heat transfer model are based on thermal data from M256 tubes. These refinements include the improvement/incorporation of case gas cooling effects, turbulent gas mixing/heating effects, and a very minor contribution from forcing cone-induced vena contracta cooling effects. These latter refinements are calibrated away from crack walls by positional thermal wall repacking depth, thermal wall transformation depth, and thermocouple data. A comprehensive gun erosion model is described for the 120-mm M256 gun with its M829Ax series rounds. In addition, a detailed shot-by-shot erosion modeling prediction is escribed for retired 120-mm M256 gun tube serial #1988. For this gun tube, the erosion prediction includes the two types of rounds fired, 829 and M829A2, and their three round-conditioning temperatures, hot, ambient, and cold. The gun erosion mechanism consists of heat checking the inert chromium plate, subsequent interfacial degradation of the subsurface gun steel substrate at the chromium crack bases, then chromium platelet spalling, and subsequent bare gun steel gas wash. This gun erosion model correctly calculates and predicts that the worst eroded region is at 1.2 to 2.4 meters from the rear face of the tube.
Book Synopsis Modeling of Erosive Combustion Products Affecting the 120-MM M256/M829A2 Gun System by :
Download or read book Modeling of Erosive Combustion Products Affecting the 120-MM M256/M829A2 Gun System written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MACE gun barrel erosion code is used to thermochemically model erosive combustion products affecting the 0.005-inch high contraction (HC) chromium plated A723 steel 120-mm M256/ambient temperature-conditioned M829A2 gun system for a single-round firing scenario. The HC chromium plate, the subsurface A723 steel substrate at HC chromium crack bases, and bare A723 steel are evaluated. This gun erosion analysis includes the standard interior ballistics gun code (XNOVAKTC), the standard nonideal gas-wall thermochemical rocket code modified for guns (CCET), the standard mass addition boundary layer rocket code modified for guns (MABL), and the standard wall material ablation conduction code modified for guns (MACE). Specifically, this new variation of the gun erosion analysis uses MACE wall temperatures as a function of time/position/depth, as well as their associated gas pressures as a function of time/position to thermochemically compute differences in combustion products for the various reacting and nonreacting walls allowing erosive combustion products to be identified. Identification of erosive combustion products by comparative modeling between proposed and present propellant formulations or between a propellant formulation with and without additives may benefit current U.S. Army/Navy programs that attempt to lower propellant flame temperature and/or propellant erosion. Carbon dioxide, water, and carbon monoxide are the identified erosive combustion products for this gun system.
Book Synopsis Shot-by-shot Erosion Modeling of Retired 120mm M256 Gun Tube Number 1988 by : Samuel Sopok
Download or read book Shot-by-shot Erosion Modeling of Retired 120mm M256 Gun Tube Number 1988 written by Samuel Sopok and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ablative Erosion Model for the M256/M829E3 Gun System by :
Download or read book Ablative Erosion Model for the M256/M829E3 Gun System written by and published by . This book was released on 2001 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A combination of bore-protecting ablative and bore-coating technologies is necessary to reduce erosion for current and future high-performance gun systems. Our cannon coating erosion model developed in 1996 is fully capable of incorporating the added complexity of bore-protecting ablatives. Both nonablative and ablative results from this model have been published for a number of important Army and Navy gun systems with bore coatings. This erosion model is guided and calibrated and correlates very well with substantial gun system firing data and subsequent laboratory analysis of fired specimens. Additionally, the model uses measured ablative flow and thermal decomposition data to determine the ablative mechanisms and guide/calibrate ablative modeling. The purpose of this report is to show how our ablative model incorporates into our overall cannon coating erosion code by using the experimental ablative M256/MS29E3 gun system as an illustrative example. Although we do not have authority to release the composition and processing of this proprietary ablative paste, we do have authority to release its general thermal decomposition, flow characteristics, and ablative mechanism data. These decomposition, flow, and ablative mechanism data are used by the thermochemical, boundary layer, and thermal and erosion modeling codes to include the effect of the ablative paste and its associated thermal decomposition products. Experimental ablative M829E3 rounds-to-erosion condemnation at the peak eroded 1.6-meter from the rear face of the tube position determines this gun system's predicted erosion life. At that position, the respective 49 deg C, 21 deg C, and -32 deg C round-conditioning temperature cases achieve predicted erosion condemnation at approximately 240, 390, and 350 rounds.
Book Synopsis 35th AIAA Thermophysics Conference by :
Download or read book 35th AIAA Thermophysics Conference written by and published by . This book was released on 2001 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Cannon Coating Erosion Modeling Achievements by :
Download or read book Cannon Coating Erosion Modeling Achievements written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our repeatedly verified erosion theories are derived from many years of conducting the Army's mission of characterizing a broad spectrum of fired and eroded cannons. Based on these characterizations, we chronicle the establishment, development, achievement, and advancement of the first practical cannon and cannon coating/ablative erosion models for large and medium caliber gun systems. The U.S. Army Research Laboratory's subsequent confirmation and adoption of our cannon and cannon coating/ablative erosion theories and models is also chronicled. This new method, in conjunction with limited-scale firings, has greatly increased the Army's technical capability and provides a reliable and cost effective means of comprehensively studying the erosion of coated cannon bores that previously required costly full-scale firings. Our comprehensive cannon erosion theories, models, and predictions have been widely embraced by Army and Navy program managers, saving them millions of dollars, and having a far-reaching impact on gun system design, optimization, and testing. Initially we discuss our early erosion theories and limited erosion models. Then we continue in chronological order with a discussion of our first practical cannon erosion model with an advanced artillery gun system example. Next, we discuss the extension of this initial model to our first practical cannon coating/ablative erosion model with an advanced medium caliber gun system example. We then discuss the adaptation of our cannon coating/ablative erosion model to advanced tank gun systems. Finally, we conclude with a description of our recent erosion modeling efforts. The following is a description of the methodology that has been established, developed, and applied to address the current Army problem of cannon bore erosion on advanced gun systems.
Download or read book Tom Stoppard Joins the Fray written by and published by . This book was released on 1981 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis LC-CR Plated Crusader Gun System Erosion Modeling by : S. Sopok
Download or read book LC-CR Plated Crusader Gun System Erosion Modeling written by S. Sopok and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis 120-mm Gun Tube Erosion Including Surface Chemistry Effects by :
Download or read book 120-mm Gun Tube Erosion Including Surface Chemistry Effects written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theoretical model that addresses thermochemical erosion in gun tubes is presented. The model incorporates two interior ballistics codes-XKTC and IBHVG2-and the thermochemical code BLAKE to provide the necessary state variables and bulk species concentrations of the core flow as input. This erosion model utilizes a Crank-Nicolson integration scheme, with dynamic gridding capability to account for material ablation, as well as the addition of energy sources and heat transfer augmentation due to surface deviations. A mass transport scheme, utilizing the Lennard Jones 6-12 diffusion model, enables individual species to be transported to the surface from the core flow. Also fully coupled is a separate thermochemical routine which incorporates the NASA Lewis database. The code is written modularly, enabling the inclusion and modification of existing submodules. Erosion results comparing a fielded kinetic energy tank round and a candidate next generation tank round are presented. The thermochemical effects at the surface are also shown and discussed.
Book Synopsis Thermochemical Erosion Modeling of the 25mm M242/M791 Gun System by :
Download or read book Thermochemical Erosion Modeling of the 25mm M242/M791 Gun System written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MACE gun barrel thermochemical erosion modeling code addresses wall degradations due to transformations, chemical reactions, and cracking coupled with pure mechanical erosion for the 25-mm M242/M791 gun system. This predictive tool provides gun system design information that is otherwise impractical. The nitrided A723 and 0.002-inch plated chromium/A723 wall materials are evaluated for erosion using the M242 Cycle A firing scenario. This complex computer analysis is based on rigorously evaluated scientific theory that has been validated in the rocket community over the last forty years. Our gun erosion analysis includes the standard interior ballistics gun code (XNOVAKTC), the standard nonideal gas-wall thermochemical rocket code modified for guns (CCET), the standard mass addition boundary layer rocket code modified for guns (MABL), and the standard wall material ablation conduction erosion rocket code modified for guns (MACE). This analysis provides wall material erosion predictions and comparisons (ablation, conduction, and erosion profiles) as a function of time, travel (customer-selected 6-inch, 12-inch, 30-inch), and number of rounds to barrel condemnation. These M242/M791 gun system predictions agree well with the standard wall heat transfer/temperature profile code (FDHEAT) and actual measured gun system erosion data.
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1032 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Gray Layers and the Erosion of Chromium Plated Gun Bore Surfaces by :
Download or read book Gray Layers and the Erosion of Chromium Plated Gun Bore Surfaces written by and published by . This book was released on 1999 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present report describes observations and analyses in a survey study of erosion damage in chromium plated gun bore surfaces. Sections of three fired chromium plated 120-mm M256 gun tubes and two 155-mm gun tubes (M199 and XM297) were examined by optical microscopy, laser scanning confocal microscopy (LSCM), and electron microprobe analyses. These tubes experienced significant erosion damage and chromium loss. A rifled portion of the 155-mm M199 tube was plated with low contractile (LC) chromium and the 155-mm XM297 and 120-mm M256 tubes were plated with high contractile (HC) chromium. New insights regarding the erosion process and the origin of chromium loss are obtained by investigation of the initial damage to the steel at the tips of the fine cracks in the chromium. Reaction products from gas-metal interactions at the gun bore surface are normally difficult to find because of gas wash effects. Examination of unetched specimens from a variety of fired tubes shows that these products remain in lace in the relatively protected regions beneath the chromium when chromium crack widths are small. The initial damage is manifested as gray layers or gray regions in the steel at the tips of the fine chromium cracks. Electron microprobe analyses indicate that these gray layers are composed of iron sulfide, iron oxide, or mixtures of the two compounds.
Book Synopsis Jane's International Defense Review by :
Download or read book Jane's International Defense Review written by and published by . This book was released on 2004 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fairchild-Republic A/OA-10 Warthog by : Dennis R. Jenkins
Download or read book Fairchild-Republic A/OA-10 Warthog written by Dennis R. Jenkins and published by Specialty Press (MN). This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This top-flight series provides a review of the world's most exciting combat aircraft.
Book Synopsis The Anti-Tank Rifle by : Steven J. Zaloga
Download or read book The Anti-Tank Rifle written by Steven J. Zaloga and published by Bloomsbury Publishing. This book was released on 2018-01-25 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emergence of the tank in World War I led to the development of the first infantry weapons to defend against tanks. Anti-tank rifles became commonplace in the inter-war years and in the early campaigns of World War II in Poland and the Battle of France, which saw renewed use in the form of the British .55in Boys anti-tank rifle - also used by the US Marine Corps in the Pacific. The French campaign made it clear that the day of the anti-tank rifle was ending due to the increasing thickness of tank armour. Nevertheless, anti-tank rifles continued to be used by the Soviets on the Eastern Front with two rifles, the 14.5mm PTRS and PTRD, and were still in widespread use in 1945. They served again with Korean and Chinese forces in the Korean War, and some have even appeared in Ukraine in 2014–15. Fully illustrated and drawing upon a range of sources, this is the absorbing story of the anti-tank rifle, the infantryman's anti-armour weapon during the world wars.
