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 Numerical Calculation and Uncertain Optimization of Energy Conversion in Interior Ballistics Stage

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5824
Author(s):  
Tong Xin ◽  
Guolai Yang ◽  
Liqun Wang ◽  
Quanzhao Sun
Keyword(s):  
Energy Conversion ◽  
Back Propagation ◽  
Element Model ◽  
Interval Uncertainty ◽  
Optimization Strategy ◽  
Interior Ballistics ◽  
Gun Barrel ◽  
Heat Efficiency ◽  
Calculation Results ◽  
Gun Firing

Gun firing is a process that converts propellant chemical energy to projectile kinetic energy and other kinds of energies. In order to explore the energy conversion process, firstly, the interior ballistics mathematical model and the barrel-projectile finite element model are built and solved. Then, the related variable values and energy values are obtained and discussed. Finally, for improving energy efficiency, the interval uncertainty optimization problem is modeled, and then solved using the two-layer nested optimization strategy and back-propagation (BP) neural network surrogate model. Calculation results show that, after optimization, the heat efficiency raises from 31.13% to 33.05% and the max rifling stress decreases from 893.68 to 859.76 Mpa, which would improve the firing performance and prolong the lifetime of the gun barrel.

Determination of a Critical Forming Parameter for the Cross-Wedge Rolling of Tubes

2005 ◽  
Author(s):  
Clint A. Morrow ◽  
Michael R. Lovell ◽  
Qiang Li
Keyword(s):  
Finite Element ◽  
Relative Motion ◽  
Tribological Behavior ◽  
Element Model ◽  
Tubular Structures ◽  
Cross Wedge Rolling ◽  
Dynamic Finite Element ◽  
The Cross ◽  
Explicit Dynamic

An explicit dynamic finite element model is used to analyze the tribological behavior of the cross-wedge rolling (CWR) of tubular structures. Cross-wedge rolling is a manufacturing process used to form axisymmetric parts by the relative motion of two opposing hardened dies. To date, the CWR process has been used to form only solid parts. In the present investigation, results are presented for the counteraction of flat dies that are used to deform tubular structures. By combining, numerical and experimental evidence, a critical forming parameter is developed which predicts the critical rolling conditions for the CWR forming of tubular structures. This parameter combines the effects of friction, wall thickness to radius reduction, and tube hardness.

scholarly journals Design and bulletproof performance investigation on the ceramic/metal laminated composite

2020 ◽  
Vol 29 ◽  
pp. 2633366X2094321
Author(s):  
Bianhong Li ◽  
Hongbin Deng ◽  
Xiangsheng Gao ◽  
Hanjun Gao
Keyword(s):  
Steel Plate ◽  
Laminated Composite ◽  
Element Model ◽  
Penetration Process ◽  
Area Density ◽  
Dynamic Finite Element ◽  
Explicit Dynamic ◽  
The Impact ◽  
Optimal Type ◽  
Ansys Workbench

In the current study, seven types of laminated composites are designed to replace the existing 616 steel plate with 5 mm thickness for the bulletproof. An explicit dynamic finite element model is developed to simulate the bullet penetration process using ANSYS Workbench software. And a specific bulletproof coefficient, which considers the ultimate bulletproof speed and area density of the target plate, is proposed and calculated, and the overall bulletproof performances of the composites and 616 steel plate are compared. The specific bulletproof coefficients of seven composites are increased by 12.53%, 14.77%, 13.28%, 12.20%, 19.59%, 23.81%, and 20.67%, respectively. The type F is the optimal type among all the structures. Eventually, the optimal composites are validated under different bullet hit positions and double-bullet situations. Results show that all the seven composites and 616 steel with 5 mm thickness can effectively defend 5.62 mm bullets, and no damage or failure is observed. Although the impact stiffness and ultimate bulletproof speed are both decreased, the area density and density are also significantly decreased.

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.

A Numerical Study on Vibrations of a Roller Bearing With a Surface Crack in the Races

2017 ◽  
Author(s):  
Jing Liu ◽  
Zhifeng Shi ◽  
Yimin Shao ◽  
Boyang Shi ◽  
Zhongjian Tian ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Surface Crack ◽  
Roller Bearing ◽  
Element Model ◽  
Dynamic Finite Element ◽  
Roller Bearings ◽  
Slant Surface ◽  
Explicit Dynamic ◽  
Bearing System

Vibrations of roller bearings will be affected when a surface crack is caused in the bearing system. Thus, it is very helpful to study relationships between the sizes of the surface crack and vibrations of the bearings for detecting and diagnosing the surface crack in the bearing systems. In this study, a dynamic finite element model for a roller bearing with a vertical or slant surface crack on its outer race is presented using an explicit dynamic finite element software package. All components of the roller bearing are formulated as elastic bodies in the finite element model, which can consider the elastic deformations in the bearing system. Effects of the depth and slope angle of the surface crack on the contact forces between the roller and races of the bearing are studied, as well as the vibrations of the bearing. The simulation results show that the explicit dynamic finite element analysis method can be applied for studying the vibration characteristics produced by a vertical or slant surface crack in roller bearings.

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