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.

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 Numerical Simulation of Non-Homogeneous Viscous Debris-Flows Based on the Smoothed Particle Hydrodynamics (SPH) Method

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2314 ◽  
Author(s):  
Shu Wang ◽  
Anping Shu ◽  
Matteo Rubinato ◽  
Mengyao Wang ◽  
Jiping Qin
Keyword(s):  
Debris Flow ◽  
Water Content ◽  
Smoothed Particle Hydrodynamics ◽  
Debris Flows ◽  
Sph Method ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
The Impact ◽  
Kinetic And Potential Energies

Non-homogeneous viscous debris flows are characterized by high density, impact force and destructiveness, and the complexity of the materials they are made of. This has always made these flows challenging to simulate numerically, and to reproduce experimentally debris flow processes. In this study, the formation-movement process of non-homogeneous debris flow under three different soil configurations was simulated numerically by modifying the formulation of collision, friction, and yield stresses for the existing Smoothed Particle Hydrodynamics (SPH) method. The results obtained by applying this modification to the SPH model clearly demonstrated that the configuration where fine and coarse particles are fully mixed, with no specific layering, produces more fluctuations and instability of the debris flow. The kinetic and potential energies of the fluctuating particles calculated for each scenario have been shown to be affected by the water content by focusing on small local areas. Therefore, this study provides a better understanding and new insights regarding intermittent debris flows, and explains the impact of the water content on their formation and movement processes.

scholarly journals Cratering for Impact of Hypervelocity Projectiles into Granite Targets within a Velocity Range of 1.91–3.99 km/s: Experiments and Analysis

2020 ◽  
Vol 10 (4) ◽  
pp. 1393
Author(s):  
Xiaofeng Wang ◽  
Jingbo Liu ◽  
Biao Wu ◽  
Defeng Kong ◽  
Jiarong Huang ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Scaling Law ◽  
Density Ratio ◽  
Hypervelocity Impact ◽  
Experimental Results ◽  
Tungsten Alloy ◽  
Regression Equations ◽  
Velocity Range ◽  
Predicted Values ◽  
The Impact

To understand and analyze crater damage of rocks under hypervelocity impact, the hypervelocity impact cratering of 15 shots of hemispherical-nosed cylindrical projectiles into granite targets was studied within the impact velocity range of 1.91–3.99 km/s. The mass of each projectile was 40 g, and the length–diameter ratio was 2. Three types of metal material were adopted for the projectiles, including titanium alloy with a density of 4.44 g/cm3, steel alloy with a density of 7.81 g/cm3, and tungsten alloy with a density of 17.78 g/cm3. The projectile–target density ratio (ρp/ρt) ranged from 1.71 to 6.86. The depth–diameter ratios (H/D) of the craters yielded from the experiments were between 0.14 and 0.24. The effects of ρp/ρt and the impact velocity on the morphologies of the crater were evaluated. According to the experimental results, H/D of craters is negatively correlated with the impact velocity, whereas the correlation between H/D and ρp/ρt is weak positive. The crater parameters were expressed as power law relations of impact parameters by using scaling law analysis. The multiple regression analysis was utilized to obtain the coefficients and the exponents of the relation equations. The predicted values of the regression equations were close to the experimental results.

An Examination of DOP Test of Ceramic Tile Subjected to Long Rod Penetration

2014 ◽  
Vol 566 ◽  
pp. 353-358
Author(s):  
Jian Ming Yuan ◽  
Geoffrey E.B. Tan
Keyword(s):  
Numerical Solution ◽  
Impact Velocity ◽  
Ceramic Tile ◽  
Tungsten Alloy ◽  
Ceramic Tiles ◽  
Depth Of Penetration ◽  
Ballistic Performance ◽  
Long Rod ◽  
Multilayered Materials ◽  
The Impact

Depth of penetration (DOP) test of ceramic tile subjected to long rod impact was analyzed by applying the Tate model. This paper investigated the influence of impact velocity and tile thickness on the ballistic performance measurement of the tested ceramic tiles. DOP test was simplified as an eroding rod penetrating a target composed of multilayered materials. Through applying the Tate model, the method of obtaining the numerical solution was proposed. For a constant impact velocity, it was found that the measured differential tile efficiency (DEF) was independent of the thickness of the ceramics tiles. But the measured DEF decreased as the impact velocity increased. These analytical conclusions were verified by the using of the results of DOP tests of SiC and Al2O3 tiles subjected to impact of long tungsten alloy rods at a nominal impact velocity of 1.3 km/s.

scholarly journals Incompressible SPH Model for Simulating Violent Free-Surface Fluid Flows

2014 ◽  
Vol 61 (1-2) ◽  
pp. 61-83
Author(s):  
Ryszard Staroszczyk
Keyword(s):  
Free Surface ◽  
Vertical Wall ◽  
Fluid Motion ◽  
Time History ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
History Of ◽  
Smoothed Particle ◽  
Incompressibility Constraint ◽  
The Impact

Abstract In this paper the problem of transient gravitational wave propagation in a viscous incompressible fluid is considered, with a focus on flows with fast-moving free surfaces. The governing equations of the problem are solved by the smoothed particle hydrodynamics method (SPH). In order to impose the incompressibility constraint on the fluid motion, the so-called projection method is applied in which the discrete SPH equations are integrated in time by using a fractional-step technique. Numerical performance of the proposed model has been assessed by comparing its results with experimental data and with results obtained by a standard (weakly compressible) version of the SPH approach. For this purpose, a plane dam-break flow problem is simulated, in order to investigate the formation and propagation of a wave generated by a sudden collapse of a water column initially contained in a rectangular tank, as well as the impact of such a wave on a rigid vertical wall. The results of simulations show the evolution of the free surface of water, the variation of velocity and pressure fields in the fluid, and the time history of pressures exerted by an impacting wave on a wall.

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.

A Development of a SPH Model for Simulating Surface Erosion by Impact(s) of Irregularly Shaped Particles

2018 ◽  
Vol 15 (08) ◽  
pp. 1850074 ◽  
Author(s):  
Xiangwei Dong ◽  
Zengliang Li ◽  
Zirui Mao ◽  
Tao Lin
Keyword(s):  
Erosive Wear ◽  
Ductile Material ◽  
Surface Erosion ◽  
Mesh Free ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
Smoothed Particle ◽  
Erosion Mechanisms ◽  
The Impact ◽  
Angular Particles

Modeling and studying the impact of angular particles are very helpful in understanding the fundamental mechanisms of erosive wear. However, the majority of previous studies focused on well-defined symmetrical particles, which are not well representative of the abrasive particles. Hence, this study develops a mesh-free model based on the smoothed particle hydrodynamics (SPH) method to simulate impact(s) of single and multiple irregularly shaped particles on ductile material. A novel procedure is proposed to model the particle as a polygonal rigid body through measuring the corner vertices. Simulations are carried out by varying the input conditions and by using different types of angular particles. Common erosion mechanisms such as cutting, machining, ploughing, prying-off are successfully reproduced by the model. The predicted crater is compared with available experimental data, and good agreement has been achieved. The proposed SPH model and out present study could be useful in the study of erosive wear on the surface of metal devices that carries granular substances.

3D Simulation of Drop Impact on Dry Surface Using SPH Method

2018 ◽  
Vol 15 (03) ◽  
pp. 1850011 ◽  
Author(s):  
Xiufeng Yang ◽  
Song-Charng Kong
Keyword(s):  
Surface Tension ◽  
Impact Velocity ◽  
Free Particle ◽  
Particle Method ◽  
Drop Impact ◽  
Sph Method ◽  
Spherical Drop ◽  
Mesh Free ◽  
Particle Hydrodynamics ◽  
The Impact

The purpose of this paper is to present and illustrate a smoothed particle hydrodynamics (SPH) method to study the process of a drop impacting on a dry solid surface. SPH is a Lagrangian mesh-free particle method that offers advantages in modeling the evolution of the liquid surface during drop impact. A new surface tension model is used. The artificial viscosity is also used, which is demonstrated to be, approximately, a linear function of the dynamic viscosity of the liquid. The SPH method is used to simulate different liquid drops impacting on dry surfaces. The numerical results agree with experimental data obtained from the literature. The influence of various parameters on the drop impact, including impact velocity, diameter, viscosity, surface tension, and density of the drop, is also studied. The results show that the dimensionless spreading diameter of the drop increases if the impact velocity, diameter, or density increases, while the increase in viscosity and surface tension decreases the spreading diameter. The results indicate that the drop impact depends more strongly on the viscosity and impact velocity than on the diameter, surface tension, and density of the drop. In addition to the impact of a spherical drop, the impact of an ellipsoidal drop on a dry surface is also studied. The results show that the aspect ratio of the drop has a significant influence on the outcome of drop impact.

scholarly journals SPH Simulation of Structures Impacted by Tailing Debris Flow and Its Application to the Buffering Effect Analysis of Debris Checking Dams

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Qing-Yun Zeng ◽  
Jian-Ping Pan ◽  
Han-Zheng Sun
Keyword(s):  
Debris Flow ◽  
Simulation Model ◽  
Flow Direction ◽  
Effect Analysis ◽  
Elastic Plastic ◽  
Particle Hydrodynamics ◽  
Sph Model ◽  
And Migration ◽  
Sph Simulation ◽  
The Impact

Since the tailing dam fails catastrophically with substantial instantaneous deformation, it is difficult to measure the migration of debris flow caused by the failure of the tailings dam. A simulation model of tailing debris flow based on Smoothed Particle Hydrodynamics (SPH) theory of elastic-plastic constitutive equation has been established by considering the viscoplasticity of mud and the elastic-plastic characteristics of tailing sand to investigate the impact effect of tailing flow on the downstream structures. By comparing the experimental and two different simulation results obtained, it can be concluded that SPH elastic-plastic constitutive model can effectively simulate the accumulation and migration processes of the tailing debris flow, which indicates that the SPH model has good applicability to solve geotechnical large deformation problems of similar tailings flow slide. Then, the verified simulation model developed based on a series of simulations of tailing debris flow propagations was used to determine the momentum reduction on the downstream structure resulting from the presence of a simple checking dam perpendicular to the direction of propagation and to determine the characteristics of stresses applied to this structure in terms of peak impact force and evolution over time to the main flow direction.

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.

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