Effect of projectile nose shape, impact velocity and target thickness on the deformation behavior of layered plates

2008 ◽  
Vol 35 (1) ◽  
pp. 37-60 ◽  
Author(s):  
N.K. Gupta ◽  
M.A. Iqbal ◽  
G.S. Sekhon
Keyword(s):  
Impact Velocity ◽  
Deformation Behavior ◽  
Target Thickness ◽  
Layered Plates ◽  
Nose Shape

NUMERICAL INVESTIGATIONS ON EFFECTS OF IMPACT VELOCITY AND SPRAY ANGLE OF PARTICLE ON ITS DEFORMATION BEHAVIOR IN COLD SPRAYING

2006 ◽  
Vol 13 (05) ◽  
pp. 613-620 ◽  
Author(s):  
XINPING ZHANG ◽  
XUEZHENG WANG ◽  
YUXUAN LI ◽  
GUANG CHEN
Keyword(s):  
Impact Velocity ◽  
Deformation Behavior ◽  
Cold Spraying ◽  
Spray Angle ◽  
High Particle ◽  
Localized Heating ◽  
Major Factors ◽  
The Impact ◽  
Contact Pressures ◽  
Spraying Process

The cold spraying process is analyzed by numerical modeling of the impact between a single spherical particle and a substrate; the effects of impact velocity and spray angle of a particle on the particle and substrate deformation behavior were investigated. It was found that much localized stress, localized strain, and localized heating are present near the particle/substrate interface. When impact velocity exceeds a critical velocity, a jet-type flow of material at the interface was formed. High particle/substrate contact pressures and better developed interfacial jets appear to be the major factors controlling the strength of interfacial bonding. As the particle impact velocity or spray angle increases, the length of interfacial jets increases and it may strengthen the bonding of the particle and the substrate.

Target Size Effects on Foreign Object Damage in Gas-Turbine Grade Silicon Nitrides by Ceramic Ball Projectiles

2010 ◽  
Author(s):  
Sung R. Choi ◽  
Zsolt Ra´cz
Keyword(s):  
Silicon Nitride ◽  
Gas Turbine ◽  
Impact Velocity ◽  
Impact Damage ◽  
Target Thickness ◽  
Foreign Object ◽  
Silicon Nitrides ◽  
Foreign Object Damage ◽  
Post Impact ◽  
Grade Silicon

Foreign object damage (FOD) phenomena of two gas-turbine grade silicon nitrides (AS800 and SN282) were determined at ambient temperature using impact velocities ranging from 25 to 150 m/s by 1.59-mm diameter silicon nitride ball projectiles. Targets in flexure bar configuration with two different thicknesses of 1 and 2 mm were impacted under a fully supported condition. The degree of impact damage as well as of post-impact strength degradation increased with increasing impact velocity, increased with decreasing target thickness, and was greater in SN282 than in AS800 silicon nitride regardless of target thickness. The critical impact velocity, in which targets fractured catastrophically, decreased monotonically with decreasing target thickness and was lower in SN282 than in AS800. Backside cracking was dominant in both AS800 and SN282 target specimens with a thickness of 1 mm, occurring from an impact velocity of 50 m/s. A backside cracking analysis based on the elastic foundation approach was made as a function of target thickness. Overall, FOD by ceramic projectiles was significantly greater than that by hardened metallic counterparts.

Dynamic Fracture of Layered Plates Subjected to In-Plane Bending

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Servesh Kumar Agnihotri ◽  
Venkitanarayanan Parameswaran
Keyword(s):  
Dynamic Loading ◽  
Impact Velocity ◽  
High Speed ◽  
Thermal Protection ◽  
Strain History ◽  
High Speed Imaging ◽  
Layered Plates ◽  
Pmma Layer ◽  
Crack Tips ◽  
The One

Layered structures typically used in applications such as windshields, thermal protection systems, heavy armor, etc., have property jumps at the layer interfaces. Present study focuses on understanding crack initiation and propagation in such systems under dynamic loading particularly when the property jumps are across the crack front. Layered plates were fabricated by joining polymethylmethacrylate (PMMA) and epoxy sheets using an epoxy-based adhesive (Araldite). Single-edge notched (SEN) specimens were subjected to dynamic loading using a modified Hopkinson bar setup. High-speed imaging coupled with dynamic photoelasticity was used to record the crack-tip isochromatic fringes from which the stress intensity factor (SIF) history was obtained. In selected experiments, a pair of strain gages installed on surfaces of specimen was used to record the strain history in the layers, from which the SIF in each layer was obtained. The results indicated that, prior to crack extension, the strain in both layers was identical. The crack tips in the layers start extending at different time instants with the one in the relatively brittle epoxy layer extending first followed by the one in the PMMA layer. At low impact velocity, the delay obtained was significantly higher than that at high impact velocity. The speed of epoxy crack was lower initially due to the bridging of the crack by the uncracked portion of the PMMA layer till initiation of the crack in the PMMA layer. This effect reduced at higher impact velocity for which the delay was much lower and the cracks propagated at a higher-speed.

Performance of Different Projectile Nose Shapes in Normal Penetrating Armor Targets

2011 ◽  
Vol 308-310 ◽  
pp. 1420-1425 ◽  
Author(s):  
Guang Yan Huang ◽  
Shun Shan Feng ◽  
Guang Wu ◽  
Shun Ping Li
Keyword(s):  
Penetration Depth ◽  
Initial Velocity ◽  
Impact Test ◽  
Target Thickness ◽  
Velocity Range ◽  
Analysis Model ◽  
Low Velocity ◽  
Expansion Theory ◽  
Nose Shape ◽  
Cavity Expansion Theory

Based on the cavity expansion theory, an analysis model of normal penetration of slender nose projectile into armor targets was established, and the variation relation curve of penetration depth and initial velocity when initial velocity is below ballistic limit was obtained. By carrying out ballistic impact test using 85mm smoothbore gun, various projectile nose shapes and armor target thickness and their effect on damage were considered. The research results have indicated that the damage of target is mainly ductile reaming and the shape of crater is almost the same as the projectile nose embedded in the target. Within a relatively low velocity range, nose shape has a greater influence on penetration depth. In contrast, within a relatively high velocity range, the target thickness has a greater influence on penetration depth. It can provide theoretical basis for the design of projectile noses and analysis of anti-penetration performance of armor targets.

Numerical Simulation on Effect of Impact Velocity and Target Thickness in Magnesium Alloy AZ31B

2015 ◽  
Vol 787 ◽  
pp. 291-295
Author(s):  
B. Ezhil Vendhan ◽  
K.L. Hari Krishna ◽  
A.K. Lakshminarayanan
Keyword(s):  
Magnesium Alloy ◽  
Impact Velocity ◽  
Shear Force ◽  
Failure Mechanisms ◽  
Plate Thickness ◽  
Target Thickness ◽  
Light Weight ◽  
Varying Thickness ◽  
Magnesium Alloy Az31b ◽  
Simulation Results

Recent research works indicate that magnesium alloy can be used for constructing light weight armor because of its density, which is 35% lower than aluminium and 77% lower than steel and also it exhibits superior vibration damping and better failure mechanisms than the contemporary ballistic materials. In this study, numerical simulations were carried out in a monolithic magnesium AZ31B plate using AUTODYN software to understand the effect of Impact velocity and plate thickness on the deformation of target plates. The projectiles are normally impacted on target plates of varying thickness plates at different velocities. Lagrangian solver was used for meshing, in which the grid developed by the solver distorts with the material helps in eliminating the inaccuracies caused by the cell growth due to the shear force of the bullet impact. The simulation results are verified with the experimental data available in the literature.

Damages Caused by Projectile Impact

2016 ◽  
Vol 689 ◽  
pp. 29-33
Author(s):  
Adnan I.O. Zaid
Keyword(s):  
Plastic Deformation ◽  
Phase Transformation ◽  
Impact Velocity ◽  
Incident Angle ◽  
Shear Bands ◽  
Local Stress ◽  
Target Thickness ◽  
Target Plate ◽  
Reflected Waves ◽  
Plug Formation

Impact conditions involve velocities below the sonic speed, which is normally of the order few hundreds up to few thousands m/s. The implications of impact depend on projectile and target materials, impact velocity, incident angle and the mass and shape of the projectile impacting head. The superimposition of progressing and reflected waves can lead to local stress levels that exceed the material’s strength, thus causing cracks and / or fracture at significant velocities. At low impact velocities, plastic deformation normally prevails. With increasing velocities the projectile will leave a hole in the target. With decreasing target thickness, the effects range from perforation, via internal cracks, and finally to plug formation. In this paper, the damages caused by impact which include: perforation, plugs formation and their fracture, metallurgical changes e.g. shear bands, twinning, recrystallization and phase transformation and fractures both in the projectile and the target plate are presented and discussed.

scholarly journals Load Characteristics in Taylor Impact Test on Projectiles with Various Nose Shapes

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 713
Author(s):  
Jun-Cheng Li ◽  
Gang Chen ◽  
Feng-Lei Huang ◽  
Yong-Gang Lu
Keyword(s):  
Impact Velocity ◽  
Impact Analysis ◽  
Impact Test ◽  
Impact Load ◽  
Loading Test ◽  
Impact Theory ◽  
Nose Shape ◽  
Taylor Impact ◽  
Taylor Impact Test ◽  
The Impact

This study focused on the impact load produced by a projectile and its potential application in the Taylor impact test. Taylor impact tests were designed and carried out for projectiles with four types of nose shapes, and the impact deformation characteristics and variation of the impact load as a function of the nose shape and impact velocity were studied. The overall high g loading experienced by the projectile body during the impact was discussed, and based on classical Taylor impact theory, impact analysis models for the various nose-shape projectiles were established and the causes of the different impact load pulse shapes were analyzed. This study reveals that the nose shape has a significant effect on the impact load waveform and pulse duration characteristics, while the impact velocity primarily affects the peak value of the impact load. Thus, the loading of specific impact environments could be regulated by the projectile nose shape design and impact velocity control, and the impact load could be simulated. Research results support the assumption that the Taylor impact test can be applied to high g loading test.

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