Numerical Simulation of Hypervelocity Impact on Mesh Bumper Causing Fragmentation and Ejection

2012 ◽  
Vol 525-526 ◽  
pp. 401-404
Author(s):  
Gong Shun Guan ◽  
Rui Tao Niu
Keyword(s):  
Numerical Simulation ◽  
Kinetic Energy ◽  
Impact Angle ◽  
Hypervelocity Impact ◽  
Impact Position ◽  
Debris Cloud ◽  
Combination Mode ◽  
The Impact ◽  
The Relationship ◽  
Aluminum Mesh

In order to study the fragmentation of projectile and ejection of debris clouds caused by hypervelocity impacting mesh bumper, simulation of aluminum sphere projectile hypervelocity normal impacting aluminum mesh bumper was practiced with SPH arithmetic of LS-DYNA soft. The diameter of projectile was 4mm. Impact velocities of aluminum spheres were varied between 2.2km/s and 6.2km/s. The impact angle was 0°. The relationship between the debris clouds characteristic of projectile and the impact position on aluminum mesh bumper was studied. The effect on fragmentation of projectile from different combination mode of aluminum mesh bumper was analyzed. The results showed that the morphologies of the debris cloud varied with the impact position when a projectile impacted the mesh bumper. The debris clouds as palpus was found, and some local kinetic energy concentrated appeared in the debris clouds. Debris clouds distribution was more uniform when projectile impacted wire across point on the mesh bumper. Debris clouds had more diffuse area and less residual kinetic energy when mesh bumper was combined with interleaving mode. Mesh bumper combined with interleaving mode was helpful in enhancing the protection performance of shields.

Research of Performance about Ceramic Coating on Aluminum Bumper to Resist Hypervelocity Impact

2013 ◽  
Vol 577-578 ◽  
pp. 629-632
Author(s):  
Gong Shun Guan ◽  
Qiang Bi ◽  
Yu Zhang
Keyword(s):  
Kinetic Energy ◽  
Optimum Design ◽  
Critical Thickness ◽  
Ceramic Coating ◽  
Impact Angle ◽  
Hypervelocity Impact ◽  
Front Side ◽  
Gas Gun ◽  
Whipple Shield ◽  
The Impact

Shield structure based on ceramic coating on aluminum bumper was designed, and a series of hypervelocity impact tests were practiced with a two-stage light gas gun facility. Impact velocities were varied between1.5km/s and 5.0km/s. The diameter of projectiles were 3.97mm and 6.35mm respectively. The impact angle was 0°. The damage of the ceramic coating on aluminum bumper under hypervelocity impact was studied. It was found that the ceramic coating on aluminum bumper could help enhancing the protection performance of shield to resist hypervelocity impact. The results indicated when the ceramic coating is on the front side of aluminum bumper, it was good for comminuting projectile and weakening the kinetic energy of projectile. For a certain aluminum bumper, existing a critical thickness of ceramic coating in which capability of Whipple shield to resist hypervelocity impact is the best. On this basis, the proposal of the optimum design for ceramic coating on aluminum bumper was made.

Protection properties of stuffed corrugated sandwich structures under hypervelocity impact: Numerical simulation

2017 ◽  
Vol 21 (2) ◽  
pp. 532-551 ◽  
Author(s):  
Hao Zhou ◽  
Rui Guo ◽  
Rongzhong Liu
Keyword(s):  
Numerical Simulation ◽  
Sandwich Structure ◽  
Hypervelocity Impact ◽  
Orbital Debris ◽  
Protection Mechanism ◽  
Broad Application ◽  
Waves Propagation ◽  
Debris Cloud ◽  
Impact Characteristics ◽  
The Impact

The stuffed corrugated sandwich structure was proposed for the application in the protection of the spacecraft against orbital debris. In order to investigate the protection properties of the stuffed corrugated sandwich structure under hypervelocity impact, numerical simulations were carried out to analyze the impact characteristics. The hypervelocity impact process was presented and the properties such as shock waves propagation, energy absorption, and expansion of the debris cloud were discussed; corresponding properties of mass equal Whipple structure under impact were analyzed for comparison. The results illustrate the protection mechanism of the stuffed corrugated sandwich subject to hypervelocity impact and show that it has superior protection performance to monolithic plate, which prove that the stuffed corrugated sandwich structure has potentially broad application prospect in the field of spacecraft protection against the orbital debris. The research can provide reference for the design of protection shield of the spacecraft.

Experimental and Numerical Study on the Mesh Bumper by Hypervelocity Impact

2012 ◽  
Vol 457-458 ◽  
pp. 108-112
Author(s):  
Min Lin ◽  
Bao Jun Pang ◽  
Jin Cheng
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Quantitative Research ◽  
Numerical Study ◽  
Hypervelocity Impact ◽  
Impact Position ◽  
Debris Cloud

In order to systematically explore the properties of the mesh bumper under hypervelocity impact, the quantitative research of protect characteristics was carried out with the numerical simulation. The experiments, in which the projectile impacted the multi-layers mesh bumper at hypervelocity, were simulated using the Ls-Dyna hydro-codes. The results for simulations and experiments were compared and analyzed. The effectiveness and accuracy of the simulation model is proved. It is shown that the morphologies of debris cloud were obviously varied with the change of impact position.

Investigation into Damage of Stainless Steel Mesh/ALPlate Multi-Shock Shield under Hypervelocity AL-Spheres Impact

2012 ◽  
Vol 525-526 ◽  
pp. 397-400
Author(s):  
Gong Shun Guan ◽  
Dong Dong Pu ◽  
Yue Ha
Keyword(s):  
Stainless Steel ◽  
Impact Angle ◽  
Separation Distance ◽  
Hypervelocity Impact ◽  
Aluminum Plate ◽  
Optimized Design ◽  
Stainless Steel Mesh ◽  
Steel Mesh ◽  
Gas Gun ◽  
The Impact

A series of hypervelocity impact tests on stainless steel mesh/aluminum plate multi-shock shield were practiced with a two-stage light gas gun facility. Impact velocity was approximately 4km/s. The diameter of projectiles was 6.4mm. The impact angle was 0°. The fragmentation and dispersal of hypervelocity particle against stainless steel mesh bumper varying with mesh opening size and the wire diameter were investigated. It was found that the mesh wall position, diameter of wire, separation distance arrangement and mesh opening had high influence on the hypervelocity impact characteristic of stainless steel mesh/aluminum plate multi-shock shields. When the stainless steel mesh wall was located in the first wall site of the bumper it did not help comminuting and decelerating projectile. When the stainless steel mesh wall was located in the last wall site of the bumper, it could help dispersing debris clouds, reducing the damage of the rear wall. Optimized design idea of stainless steel mesh/aluminum plate multi-shock shields was suggested.

Aluminum Shield Under Hypervelocity Impact of Mylar Flyer

2008 ◽  
Author(s):  
J. Zhao ◽  
F. Tan ◽  
C. Liu ◽  
C. Sun
Keyword(s):  
High Speed ◽  
Hypervelocity Impact ◽  
Space Environment ◽  
Lateral Expansion ◽  
Near Earth Space ◽  
The Third ◽  
Naturally Occurring ◽  
Debris Cloud ◽  
The Impact ◽  
Different Thickness

The near-earth space environment is cluttered with man-made debris and naturally occurring meteoroids, which is a big menace to the safety of satellites and spacecrafts. This paper is addressed on the failure response of aluminum shields under hypervelocity impact of milligrame level flyer. A compacted electric gun is employed to accelerate a mylar flyer up to 10 km/s. Failure response of Ly12 aluminum shields with different thickness and layers impacted by mylar flyer with different velocities is under investigation. The spallation is observed in the rear free surface of 4 mm thick monolithic aluminum shield, and its fracture mechanism changes from plastic to brittle when loading pressure is above 13 GPa. A perforation with a diameter 8 mm in the impacted area of the 4mm thick Ly12 shield is observed after which is impacted by 0.1 mm thick mylar flyer 8mm in diameter with velocity 8.2 km/s. When three layers of shields are impacted, the debris clouds (DC) are observed in the first and the second spaces respectively during the impact process by high speed camera, and its leftover can be observed on the surface of the third plate. The shape of the first debris cloud head is a little flat, and its speed of lateral expansion is very slow, which is different from those impacted by spherical projectile, and its formation mechanics mainly attributes to multi-spallations based on the analysis of simulation.

Numerical Simulation of the Mechanical Structure of a Helmet Motorcyclist

2013 ◽  
Vol 856 ◽  
pp. 368-372 ◽  
Author(s):  
Bessai Naïma ◽  
Boudjemaa Fatiha ◽  
Lounis Mourad ◽  
Baumgartner Danie
Keyword(s):  
Numerical Simulation ◽  
Kinetic Energy ◽  
Road Safety ◽  
Main Function ◽  
Dynamic Reaction ◽  
Modern Life ◽  
High Importance ◽  
Protective System ◽  
Shock Impact ◽  
The Impact

Road safety is of high importance in our modern life in terms of social and economic. The helmet is the head protective system the most common used. Their main function is to reduce or prevent damage that may occur during an impact due to an accident. The head will be better protected if the more important quantity of the energy caused by the kinetic energy of the impact is absorbed by the helmet. The greater part of the impact energy should be absorbed by the deformations of the different layers of the helmet. The analytic equations of the model of the helmet parts show a realistic dynamic reaction of the different layers after the shock impact. These results will permit a better comprehension of the helmet behaviour to violent impact and the energy distribution in the different layers so a better optimisation of the head helmet in the future.

Numerical Simulation of a Dilute Particulate Flow (Laminar) Over Tube Banks

1994 ◽  
Vol 116 (4) ◽  
pp. 770-777 ◽  
Author(s):  
Yong-Du Jun ◽  
Widen Tabakoff
Keyword(s):  
Numerical Simulation ◽  
Impact Angle ◽  
Protective Role ◽  
Point Of View ◽  
Particulate Flow ◽  
Tube Bank ◽  
Semiempirical Equation ◽  
Tube Banks ◽  
Bank System ◽  
The Impact

This paper presents an investigation of numerical simulation for a dilute particle laden flow (laminar) over in-line tube banks. Particles behavior of two different sizes and density (100 μm sand and 40 μm fly ash) is demonstrated through the present study for a fixed geometry and flow condition, that is, a square in-line tube bank of two rows deep with pitch-to-diameter ratio of two at Reynolds number 400. Dilute particulate flow assumption is used and the drag force is considered as the only external force term that affects the particles behavior in the flow. Experimental rebounding data and semiempirical equation for the erosion estimation are used. It was found through the present simulation that the particles behavior of the different sizes and density in tube bank system is quite different in their trajectories, impact and the erosion pattern. The protective role of the first row of cylinders could be supported with respect to the particles collision on the cylinder but not necessarily to the erosion point of view. Also the information at impact such as the impact velocity and the impact angle which affect the erosion (Tabakoff et al., 1988) can be estimated by using the numerical simulation shown in the present study.

scholarly journals Numerical Simulation of Borehole Parameters for Coal Seam Gas Pre-Drainage

2021 ◽  
Vol 39 (4) ◽  
pp. 1328-1334
Author(s):  
Xiaoyan Li ◽  
Jiyu Zheng ◽  
Jinpin Liu
Keyword(s):  
Numerical Simulation ◽  
Pressure Drop ◽  
Gas Pressure ◽  
Borehole Diameter ◽  
Gas Drainage ◽  
Drainage Time ◽  
Drainage Radius ◽  
Simulation Results ◽  
The Impact ◽  
The Relationship

Borehole parameters are quite important for gas drainage. This paper studies the impact of borehole diameter and time on gas drainage and performs numerical simulation on the distribution of gas pressure under the conditions of different borehole diameters and drainage times. The simulation results reveal that, as the borehole diameter increases, the gas drainage volume increases along with it and the gas pressure decreases, but such effect on gas drainage is limited. In terms of drainage time, the longer the drainage time, the greater the drainage impact scope. Taking a gas pressure drop of 51% as the indicator of the effective pre-drainage radius, the distance from the point with a gas pressure drop of 51% to the position of the borehole is the effective pre-drainage radius. When the pre-drainage reached the 30th, 45th, 60th, 75th, and 90th day, the effective pre-drainage radius was 1.04m, 1.29m, 1.51m, 1.68m, and 1.82m respectively. According to the numerical simulation results, the effective pre-drainage radius varies with the pre-drainage time, and the fitting analysis of the two indicates that the relationship between the two can be described by a power function.

scholarly journals Atmospheric teleconnection patterns and eddy kinetic energy content: wavelet analysis

2004 ◽  
Vol 11 (3) ◽  
pp. 295-301 ◽  
Author(s):  
V. N. Khokhlov ◽  
A. V. Glushkov ◽  
I. A. Tsenenko
Keyword(s):  
Kinetic Energy ◽  
North Atlantic ◽  
Energy Content ◽  
Southern Oscillation ◽  
Eddy Kinetic Energy ◽  
The North ◽  
The North Atlantic ◽  
The Impact ◽  
The Relationship

Abstract. In this paper, we employ a non-decimated wavelet decomposition to analyse long-term variations of the teleconnection pattern monthly indices (the North Atlantic Oscillation and the Southern Oscillation) and the relationship of these variations with eddy kinetic energy contents (KE) in the atmosphere of mid-latitudes and tropics. Major advantage of using this tool is to isolate short- and long-term components of fluctuations. Such analysis allows revealing basic periodic behaviours for the North Atlantic Oscillations (NAO) indices such as the 4-8-year and the natural change of dominant phase. The main results can be posed as follows. First, if the phases of North Atlantic and Southern Oscillations vary synchronously with the 4-8-year period then the relationship between the variations of the NAO indices and the KE contents is the most appreciable. Second, if the NAO phase tends to abrupt changes then the impact of these variations on the eddy kinetic energy contents in both mid-latitudes and tropics is more significant than for the durational dominance of certain phase.

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