Mechanism of Interior Ballistic Peak Phenomenon of Guns and Its Effects

2010 ◽  
Vol 77 (5) ◽  
Author(s):  
Chenli Tao ◽  
Yurong Zhang ◽  
Sanqun Li ◽  
Changzhi Jia ◽  
Yongjian Li ◽  
...  
Keyword(s):  
Test Data ◽  
Maximum Pressure ◽  
Ballistic Performance ◽  
Double Peak ◽  
Interior Ballistics ◽  
Firing Test ◽  
Gun Barrel ◽  
Lumped Parameter ◽  
Fundamental Cause ◽  
Good Agreement

The erosion and wear in the gun barrel will get worse with an increase in the number of projectiles fired. Generally speaking, the ballistic performance of the gun, measured through indicators such as the maximum pressure pm and the muzzle velocity v0, will decrease gradually due to gun barrel erosion. However, the above analysis does not agree with the firing test data of certain types of guns, especially of some small-caliber guns. The ballistic performance of such guns will exhibit an increase to their peak values followed by a gradual decrease with the number of rounds fired. This is the so-called interior ballistic peak phenomenon, also named as the hump effect. Taking several kinds of guns as examples, such as a 76 mm gun and a 100 mm gun, we calculated the engraving pressure p0 of the guns by an approximate method and built a lumped-parameter interior ballistic model of the guns that exhibits the effect, according to the interior ballistics theory of guns with erosion and wear. The results of the modeling of the guns under different wear conditions are close to the test data, showing the existence of the peak values of pm and v0. The simulation results of some of the other guns that exhibit this phenomenon also show good agreement. Furthermore, it can explain the double-peak phenomenon for some types of guns with double driving bands. It was proven that the mismatch of the structure and the dimensions of the gun bore with those of the projectile driving band is the fundamental cause of this effect. Due to the mismatch, the engraving pressure will first increase and then decrease with the enlargement of the bore dimensions caused by barrel erosion and wear. The variation in the engraving pressure p0 will inevitably lead to the variation in interior ballistic performance in the life cycle of the gun. This observed process appears to explain the interior ballistic peak phenomenon.

Advanced Gun System Gun and Projectile Dynamic Model Results and Correlation to Test Data

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
J. Edward Alexander
Keyword(s):  
Test Data ◽  
Development Program ◽  
Element Model ◽  
Dynamic Finite Element ◽  
Firing Test ◽  
Gun Barrel ◽  
Angular Velocities ◽  
Gun Firing ◽  
Explicit Dynamic ◽  
Abaqus Model

BAE Systems is currently developing and testing a 155 mm advanced gun system (AGS) and a long range land attack projectile (LRLAP) as a part of the DDG-1000 ship development program. For this development, it is important to understand the barrel and projectile dynamics, including the interaction of the barrel and the projectile in the bore as well as the projectile tip-off parameters at exit. An abaqus explicit dynamic finite element model has been developed to compare results with test data that were taken on June 18, 2003, at the BAE Systems site at the Alliant Techsystems Proving Ground (ATPG) during AGS propellant testing. The abaqus model includes the gun barrel, the projectile used for propellant testing (a steel slug), the M110 gun mount, and the recoil system. Features of the model incorporate settling of the barrel due to gravity, gun recoil, in-bore interaction of the projectile and the barrel using contact surfaces, and the initial flight of the projectile after bore exit. The abaqus model results have been compared with gun firing test data acquired during propellant testing at Elk River, MN. These comparisons include barrel and projectile displacements, angular velocities, and axial accelerations. The abaqus model results are also compared to similar models of the test conditions with the simulation of barrel dynamics (simbad) gun dynamics code and the ibhvg2 interior ballistics code.

scholarly journals THEORETICAL AND EXPERIMENTAL STUDY OF THE INTERIOR BALLISTICS OF A RIFLE 7.62

2014 ◽  
Vol 13 (2) ◽  
pp. 20 ◽  
Author(s):  
P. O. Cronemberger ◽  
E. P. Lima Jr. ◽  
J. A. M. Gois ◽  
A. B. Caldeira
Keyword(s):  
Lumped Parameter Model ◽  
Maximum Pressure ◽  
Projectile Velocity ◽  
Interior Ballistics ◽  
Propellant Combustion ◽  
Muzzle Velocity ◽  
Lumped Parameter ◽  
Differential Algebraic System ◽  
Lumped Parameters ◽  
Data Tables

This study aims to examine theoretically and experimentally the interior ballistics of a rifle 7.62. Three theoretical methods are employed: the Vallier-Heydenreich, which is based on empirical data tables; the lumped parameters that is represented by a differential-algebraic system of equations, describing the propellant combustion, the thermodynamics of the gas inside the gun and the projectile dynamics; and the commercial software PRODAS. The theoretical solutions furnish the pressure, the projectile velocity and the projectile position inside the gun, the maximum pressure,the muzzle velocity and the total time of the interior ballistics. The experiments measure the pressure along of the time and the projectile velocity at seven meters ahead of the barrel. The proposed lumped parameter model indicates alternatives to model the energy lost and the resistance pressure functions. The theoretical solutions are compared with experiments. A thermodynamics analysis of the energy conversion in the gun is provided. The results are analyzed and the relevance of each method is highlighted.

Two Phase Flow Modeling of the Interior Ballistics for a Naval Medium Caliber Gun with Guided Projectile

2013 ◽  
Vol 465-466 ◽  
pp. 531-535
Author(s):  
Hazem Elsadek ◽  
Xiao Bing Zhang ◽  
Mahmod M. Rashad ◽  
Cheng Cheny
Keyword(s):  
Fluid Dynamics ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Modeling ◽  
Governing Equations ◽  
Ballistic Performance ◽  
Two Phase ◽  
Interior Ballistics ◽  
Simulation Results ◽  
Good Agreement

This paper discusses the two phase (gas/Particles) flow effect of interior ballistic performance in a 76 mm naval medium caliber gun with guided projectile, using granular seven-perforated propellant. The theoretical and numerical simulation of the two phase flow in the interior ballistic cycle is carried out by using MacCromack technique depending on the governing equations of the two phase flow. This simulation is considered to be helpful for the prediction of the interior ballistic parameters which are required for endurance of guided projectile. A good agreement between the simulation results compared to the experimental results is fulfilled. Keywords: Guided projectile, two phase flow modeling, Interior ballistic, Computational fluid dynamics.

Calculation of Punch Force and Maximum Pressure for Tube Extrusion

2000 ◽  
Author(s):  
S.-H. Zhang ◽  
Y.-L. Shang
Keyword(s):  
Upper Bound ◽  
Physical Modeling ◽  
Steel Tube ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Punch Force ◽  
Tube Extrusion ◽  
Tooling System ◽  
Very High ◽  
Good Agreement

Abstract Punch force and maximum pressure for tube extrusion can be predicted with an upper bound theory-based program POLSK. Experiments of steel tube extrusion and wax physical modeling were performed. The punch force and the maximum pressure values were obtained. Comparisons were made among the experimental results, physical modeling results and upper bound predictions. It was found that a medium extrusion coefficient causes the lowest pressure on the tooling system, very low and very high extrusion coefficients can both cause very high pressure. It is proved that the upper bound predictions are in good agreement with the experimental results and the upper bound program is suitable for use of steel tube extrusion design.

scholarly journals Parameter Identification of Tractor-Semitrailer Model under Steering and Braking

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Yiming Li ◽  
Qin Shi ◽  
Duoyang Qiu
Keyword(s):  
Genetic Algorithm ◽  
Field Test ◽  
Test Data ◽  
Performance Testing ◽  
Roll Angle ◽  
Lookup Table ◽  
The Real ◽  
Yaw Rate ◽  
Roll Rate ◽  
Good Agreement

This paper describes a valuable linear yaw-roll tractor-semitrailer (TST) model with five-degree-of-freedom (DOFs) for control algorithm development when steering and braking. The key parameters, roll stiffness, axle cornering stiffness, and fifth-wheel stiffness, are identified by the genetic algorithm (GA) and multistage genetic algorithm (MGA) based on TruckSim outputs to increase the accuracy of the model. Thus, the key parameters of the simplified model can be modified according to the real-time vehicle states by online lookup table and interpolation. The TruckSim vehicle model is built referring to the real tractor (JAC-HFC4251P1K7E33ZTF6×2) and semitrailer (Luyue LHX9406) used in the field test later. The validation of the linear yaw-roll model of a tractor-semitrailer using field test data is presented in this paper. The field test in the performance testing ground is detailed, and the test data of roll angle, roll rate, and yaw rate are compared with the outputs of the model with maps of the key parameters. The results indicate that the error of the tractor’s roll angle and semitrailer’s roll angle between model data and test data is 1.13% and 1.24%, respectively. The roll rate and yaw rate of the tractor and semitrailer are also in good agreement.

Wheat quality: A factor analysis of some test data

1963 ◽  
Vol 14 (5) ◽  
pp. 603 ◽  
Author(s):  
R Jardine ◽  
HJ Moss ◽  
JV Mullaly
Keyword(s):  
Factor Analysis ◽  
Test Data ◽  
Independent Sets ◽  
Wheat Quality ◽  
Factor Analyses ◽  
Wheat Grain ◽  
Bread Making ◽  
Correlation Matrices ◽  
Sample Characteristics ◽  
Good Agreement

Seventeen tests for the measurement of wheat grain samples in respect of bread making quality have been investigated. Two (17 x 17) correlation matrices were calculated from the data yielded by the application of those tests to two series of samples, and factor analyses of those matrices were then undertaken. The analyses indicate that four oblique but relatively independent factors, designated as "strength", "hardness", "stability", and "stiffness", are sufficient to account for the correlations among tests. The two independent sets of data show good agreement as to the factor structures of the tests; and where they differ, reasonable explanations, in terms of either procedures or sample characteristics, are generally available.

INTERNAL BALLISTICS OF CLASSIC GUN WITH COMPOSITE CHARGE

2019 ◽  
Vol 147 (3/2018) ◽  
pp. 47-62
Author(s):  
Marek Radomski
Keyword(s):  
Mathematical Model ◽  
Hard Core ◽  
Combustion Products ◽  
Maximum Pressure ◽  
Muzzle Velocity ◽  
Internal Ballistics ◽  
Lumped Parameter ◽  
Model Equations ◽  
Gun Firing ◽  
Composite Charge

The paper presents a lumped parameter mathematical model considering the changes of thermodynamic properties for combustion products of a composite propelling charge, and of a burning cartridge casing or shell as well, when shot with classic guns. In addition a method was proposed for considering not coincidental instants of ignition for particular components of the charge and also for powder grains of each component, and the heat flow into the walls containing the space with combustion products. Some results of numerical computations are shown for 125 mm 2A46 tank gun firing a hard core projectile. Moreover an evaluation of accuracy of the results is given on the basis of experimental data. Maximum pressure and muzzle velocity were basic criteria at the verification of the model. Analysis of accuracy for solutions of model equations allows a conclusion that the proposed mathematical model may be useful at the designing process of ammunition and guns.

Investigation of Stick Propellant Internal Perforation Erosive Burning on Interior Ballistics Performances

2016 ◽  
Vol 67 (1) ◽  
pp. 19
Author(s):  
Xiaoliang Zhao ◽  
Xiaobing Zhang
Keyword(s):  
Numerical Simulations ◽  
Significant Influence ◽  
Combustion Process ◽  
Ballistic Performance ◽  
Interior Ballistics ◽  
Propellant Combustion ◽  
Erosive Burning ◽  
Weak Influence

In this study, a thorough investigation of a stick propellant internal perforation erosive burning on interior ballistic performances is presented via extending the previous work of author. The stick propellant combustion process and the internal perforation erosive burning are revealed by numerical simulations. Different factors with respect to the stick propellant, including propellant length, internal perforation diameter and loading density are analysed in detail. Stick propellant length and the internal perforation diameter have a significant influence on the ballistic performance, the longer and smaller internal propellant have a greater erosive burning effect to the ballistic performance. Loading density has very weak influence on the ballistic.

Temperature measurements in a hypersonic gun tunnel using heat-transfer methods

1967 ◽  
Vol 27 (3) ◽  
pp. 503-512 ◽  
Author(s):  
B. E. Edney
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Mach Number ◽  
Heat Losses ◽  
Transfer Rates ◽  
Gun Barrel ◽  
Compression Cycle ◽  
Initial Shock ◽  
Working Section ◽  
Good Agreement

The theory of Fay & Riddell (1958) is used to calculate stagnation temperatures from stagnation-point heat-transfer rates measured in the working section of a hypersonic gun tunnel at a Mach number of 9·8. Measurements using both thin-film gauges and calorimeters are described. The temperatures measured using this technique are found to be lower than predicted by Lemcke (1962) from measurements of shock strengths and final pressures in the gun barrel. This discrepancy is attributed to heat losses in the barrel during the initial shock compression cycle. A simple theory is developed to take into account these losses. There is good agreement between this theory and the experimental results.

Prediction of Fracture Appearance Transition Temperature of 2.25Cr-1Mo Steel Used in Hot-Wall Hydrofining Reactors

2005 ◽  
Vol 128 (4) ◽  
pp. 566-571 ◽  
Author(s):  
Jinzhu Tan ◽  
Wenlong Huang ◽  
Y. J. Chao
Keyword(s):  
Transition Temperature ◽  
Test Data ◽  
Electron Spectroscopy ◽  
Temper Embrittlement ◽  
Spectroscopy Analysis ◽  
Auger Electron Spectroscopy Analysis ◽  
Fracture Appearance Transition Temperature ◽  
Fracture Appearance ◽  
Predicted Values ◽  
Good Agreement

A kinetics model for temper embrittlement was employed as the basis for predicting the fracture appearance transition temperature (FATT) of 2.25Cr-1Mo steel used for hot-wall hydrofining reactors. Various heat treatments were performed to obtain different degrees of temper embrittlement for the steel. Charpy V-notch impact tests and Auger electron spectroscopy analysis were performed on embrittled 2.25Cr-1Mo steels to establish the relation between the shift of FATT and the change in the concentration of phosphorus segregated in the grain boundary of the steel. Based on the model and test data, a method of predicting the FATT at service time t was developed for the 2.25Cr-1Mo steel. Good agreement is obtained when the predicted values are compared to test data from open literature.

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