scholarly journals Fragmentation Behaviour of Radial Layered PELE Impacting Thin Metal Target Plates

2018 ◽  
Vol 68 (5) ◽  
pp. 505-511 ◽  
Author(s):  
Chun Cheng ◽  
Xi Chen ◽  
Zhonghua Du ◽  
Jilong Han ◽  
Chengxin Du ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Velocity Component ◽  
Steel Plate ◽  
Transverse Velocity ◽  
Thin Metal ◽  
Metal Target ◽  
Fragmentation Mechanism ◽  
Target Plate ◽  
Transverse Velocity Component ◽  
The Impact

The fragmentation mechanism of the penetrator with lateral effect (PELE) after perforating a thin target plate has been summarised and analysed firstly. Then the fragmentation of radial layered PELE was analysed qualitatively and verified by experiment. In the experiment, the target plates were made of 45# steel and 2A12 aluminium respectively. Qualitative analysis and experimental results show that: for normal PELE without layered, after perforating the thin metal target plate, from the bottom to the head of the projectile, the number of fragments formed by the jacket gradually increases, and the mass of the fragment decreases correspondingly. Compared with the normal PELE without layered, the radial layered PELE is less likely to break into fragments, when impacting the thin metal target plate with the same material and thickness under the same impact velocity. However, from the mechanism of the PELE, when the resistance of the target plate is large enough, and the duration of pressure is long enough, the radial layered PELE also can break into fragments with transverse velocity component. The resistance of the target plate plays an important role in the fragmentation of radial layered PELE. The radial layered PELE produced massive fragments with transverse velocity component when impacting the 45# steel plate with5 mm thickness under the impact velocity of 657.2 m/s.

scholarly journals Simulation of Fragmentation Characteristics of Projectile Jacket Made of Tungsten Alloy after Penetrating Metal Target Plate using SPH Method

2019 ◽  
Vol 69 (6) ◽  
pp. 591-598 ◽  
Author(s):  
Chun Cheng ◽  
Zhonghua Du ◽  
Xi Chen ◽  
Lizhi Xu ◽  
Chengxin Du ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Maximum Tensile Stress ◽  
Calculation Model ◽  
Tungsten Alloy ◽  
Metal Target ◽  
Target Plate ◽  
Average Mass ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
The Impact

A smooth particle hydrodynamics (SPH) model was used to simulate the fragmentation process of the jacket during penetrator with lateral efficiency (PELE) penetrating the metal target plate to study the fragmentation characteristics of PELE jacket made of tungsten alloy. The validity of the SPH model was verified by experimental results. Then the SPH model was used to simulate the jacket fragmentation under different impact velocity and thickness of target plate. The influence of impact velocity and thickness of target plate on the jacket fragmentation was obtained by analysing the mass distribution and quantity distribution of the fragments formed by the jacket. The results show that the dynamic fragmentation of tungsten alloy can be simulated effectively using the SPH model, Johnson-Cook strength model, maximum tensile stress failure criterion and stochastic failure model. When the thickness of target plate is fixed, the greater the impact velocity, the greater the pressure produced by the projectile impacting the target plate; with the increase of impact velocity, the mass of residual projectile decreases, the number of fragments formed by fragmentation of jacket increases linearly, and the average mass of fragments decreases exponentially. When the impact velocity is constant, the greater the thickness of the target plate, the longer the pressure duration by the projectile impacting the target plate; with the increase of the thickness of target plate, the mass of residual projectile decreases, the number of fragments formed by fragmentation of jacket increases linearly, and the average mass of fragments decreases exponentially. The numerical calculation model and research method adopted in this paper can be used to study the impact fragmentation of solid materials effectively.

A New Formula for Predicting the Crater Size of a Target Plate Produced by Hypervelocity Impact

2019 ◽  
Vol 17 (01) ◽  
pp. 1844004 ◽  
Author(s):  
Z. L. Zhang ◽  
T. Ma ◽  
D. L. Feng ◽  
M. B. Liu
Keyword(s):  
Impact Velocity ◽  
Hypervelocity Impact ◽  
Model Parameters ◽  
Target Plate ◽  
Sph Method ◽  
Crater Size ◽  
Steady Stage ◽  
Kernel Gradient Correction ◽  
Simulation Results ◽  
The Impact

Hypervelocity impact (HVI) of materials is usually associated with large deformations of structures, big craters, phase transition of materials and scattered debris cloud. It is difficult to predict the size of damage caused by HVI while comprehensively considering all the influencing factors for both experimental and numerical approaches. In this paper, the HVI process is modeled by using the smoothed particle hydrodynamics (SPH) method with Kernel Gradient Correction (KGC) technique. The SPH method with KGC (SPH-KGC) has been demonstrated to have better accuracy and reliability for modeling the HVI problems in our recent work. In this paper, the SPH-KGC method is used to investigate the HVI of a sphere on a target plate. The sizes of the craters produced by HVI at different initial impact velocities are obtained, and the variation of the crater size over the impact velocity is studied. According to the present simulation results, a critical velocity is identified and the increase of the crater size versus the initial impact velocity can be divided into two stages, a varying stage and a steady stage. A new empirical formula is presented for predicting the crater size of the target plate produced by HVI. This formula comprehensively considers the influence of many model parameters, such as the densities of the materials of both the projectile and the target, the sound speed of the target material, the diameter of the projectile and the thickness of the target plate. The results obtained by the presented prediction formula agree well with the experimental observations as well as the present SPH simulation results.

Fragmentation characteristics of PELE shell perforating thin metal target plate

2020 ◽  
pp. 1-12
Author(s):  
Chun Cheng ◽  
Lizhi Xu ◽  
Zhaojun Pang ◽  
Zhonghua Du ◽  
Meng Wang ◽  
...  
Keyword(s):  
Thin Metal ◽  
Metal Target ◽  
Target Plate

scholarly journals Theoretical Model of the Axial Residual Velocity of PELE Projectiles Penetrating Thin Metal Targets

Symmetry ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 776 ◽  
Author(s):  
Liangliang Ding ◽  
Wenhui Tang ◽  
Xianwen Ran ◽  
Zijian Fan ◽  
Weike Chen
Keyword(s):  
Theoretical Model ◽  
Energy Loss ◽  
Inner Core ◽  
Thin Metal ◽  
Target Plate ◽  
Residual Velocity ◽  
Important Indicator ◽  
Conservation Of Energy ◽  
The Impact ◽  
Energy Increment

With the increase of battlefield target diversity and protection mobility, the disadvantages of traditional armor piercing warheads have gradually become prominent. The conception of the PELE (penetration with enhanced lateral efficiency) projectile was thus proposed. The axial residual velocity of the projectile is a very important indicator of a PELE projectile, which mainly reflects the penetration ability of the PELE projectile. The PELE projectile is a symmetrical structure, so the collision problem can be simplified to plane collision. Furthermore, the two-dimensional plane is axisymmetric, and so it can be further simplified to one-dimensional collision. Based on simplification and assumptions, the mechanism of a PELE projectile penetrating a thin metal target plate was studied using the shock wave theory, and a theoretical model of axial residual velocity has been established in this article. The energy loss during the penetration process was divided into the following parts: the kinetic energy increment of the target plug in the impact region, the internal energy increment of the outer casing and inner core, and the shear energy dissipation of the projectile against the target plate. In addition, the specific methods of determining the energy loss of each part are given in detail. According to the conservation of energy, the approximate calculation formulae of the axial residual velocity of a PELE projectile have been deduced. Finally, the theoretical results were compared with the experimental results under different working conditions, and the results were in good agreement. Therefore, the theoretical model has application value and guiding significance in the field of engineering.

A Unique Test Facility to Measure Particle Restitution and Fragmentation

1994 ◽  
Author(s):  
S. C. Tan ◽  
P. K. Harris ◽  
R. L. Elder
Keyword(s):  
Impact Velocity ◽  
Test Facility ◽  
Target Chamber ◽  
Separation Performance ◽  
Plate Surface ◽  
Inertial Particle ◽  
Target Plate ◽  
Trajectory Calculations ◽  
Design Cycle ◽  
The Impact

This paper describes an experimental test facility for measuring particle restitution ratio and particle fragmentation where the turbulent effect of air has been minimised. The restitution ratios, which relate the particle rebound characteristics to the impact velocity (and angle), are used in a trajectory code so that rebound conditions can be calculated after a particle has collided with a wall surface. Trajectory calculations are often used to predict the separation performance of inertial particle separators in a design cycle without resorting to the expensive ‘cut and try’ method. A ‘coanda’ particle injector is used to separate particles from the airstream which then relies on its own inertia to collide with a target plate. Particle rebound occurred in an quiescent condition in a target chamber which has been isolated from the surroundings. The particle rebound velocity (and angle) is measured with a two-spot transit anemometer operating in the backscattered mode. Measurements are taken at about 1.0–1.5 mm from the target plate surface. The overall dimension of the test facility is relatively small (1.0 × 0.5 × 0.5 m) compared to a windtunnel facility due to the absence of an airflow. Some results are presented for certain materials showings the effect of impact velocity, angle and particle size.

The limiting behaviour of the turbulent transverse velocity component close to a wall

1970 ◽  
Vol 44 (3) ◽  
pp. 605-614 ◽  
Author(s):  
Kamalesh K. Sirkar ◽  
Thomas J. Hanratty
Keyword(s):  
Distribution Function ◽  
Frequency Response ◽  
Velocity Gradient ◽  
Velocity Component ◽  
Transverse Velocity ◽  
Electrochemical Techniques ◽  
Amplitude Distribution ◽  
Mean Flow ◽  
Transverse Velocity Component ◽  
Limiting Behaviour

Electrochemical techniques are used to measure the circumferential component of the velocity gradient sz at the wall of a pipe through which a turbulent fluid is flowing. The ratio of the root-mean-squared value of sz to the time-averaged velocity gradient is found to be 0·09 or 0·1, depending on whether corrections are made for frequency response. The frequency spectrum is similar to that for the component of the wall velocity gradient in the direction of mean flow. The amplitude distribution function for sz is very roughly approximated by a Gaussian distribution.

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