Determination of Ballistic Limits of GLARE 5 Fiber-Metal Laminates: The Influences of Geometry, Thickness and Stacking Sequence

2011 ◽  
Author(s):  
A. Seyed Yaghoubi ◽  
B. Liaw
Keyword(s):  
Volume Fraction ◽  
Velocity Versus ◽  
Specimen Thickness ◽  
Stacking Sequence ◽  
Ballistic Limit ◽  
Fiber Metal Laminates ◽  
Limit Velocity ◽  
Fiber Metal ◽  
Ballistic Limit Velocity

In this paper, GLARE 5 fiber-metal laminates (FMLs) of two different geometries: 152.4mm×101.6mm (6″×4″) plate and 254mm×25.4mm (10″×1″) beam and with various thicknesses and stacking sequences were impacted by a 0.22 caliber bullet-shaped projectile using a high-speed gas gun. Velocities of the projectile along the ballistic trajectory were measured at different locations. For both geometries, the incident projectile impact velocity versus the residual velocity was plotted and numerically fitted according to the classical Lambert–Jonas equation for the determination of ballistic limit velocity, V50. The results showed that V50 varied in a parabolic trend with respect to the metal volume fraction (MVF) and the specimen thickness for both geometries. It was found that by changing the geometry from a plate to a beam, the ballistic limit velocity increased. On the other hand, changing the stacking sequence had a less pronounced effect on V50 for both geometries. The quasi-isotropic beam and plate specimens offered relatively higher ballistic limit velocities compared to other types of stacking sequences in their own geometrical groups. Furthermore, the cross-ply and unidirectional beam specimens showed relatively higher V50 compared to their plate counterparts. Experimental results showed that the ballistic limit was almost the same for the quasi-isotropic layup FMLs of both plate and beam geometries.

Impact damage assessment of carbon fiber reinforced composite with different stacking sequence

2019 ◽  
Vol 54 (2) ◽  
pp. 193-203
Author(s):  
Rahul S Sikarwar ◽  
R Velmurugan
Keyword(s):  
High Speed ◽  
Stacking Sequence ◽  
High Speed Camera ◽  
Ballistic Limit ◽  
Limit Velocity ◽  
Post Impact ◽  
Damage Extent ◽  
Ballistic Limit Velocity ◽  
Energy Absorbing ◽  
The Impact

This work examines the experimental and analytical investigation of impact on the carbon/epoxy laminates of various stacking sequence. The impact tests were carried out by using gas gun equipped with high-speed camera. Projectile velocities selected were 80 m/s and 30 m/s where 80 m/s was above ballistic limit velocity and 30 m/s was below ballistic limit velocity. The impact process was recorded with high-speed camera which facilitated to identify different energy absorbing mechanisms. High-speed images were also used to measure pre-impact and post-impact velocities of the projectile accompanied by photo diode and aluminum foil method. Total energy absorbed by the laminates, which is the difference between pre-impact and post-impact kinetic energy of the projectile, was calculated for the laminates with different stacking sequences. Damage extent in the laminates of different stacking sequences were also assessed by C-Scan of the laminates. Then effect of stacking sequences on damage extent and energy absorbing capacity was established. An analytical model was proposed to predict the residual velocity of the projectile at above ballistic limit velocity, which was based on the total energy absorbed by different energy absorption mechanisms. The analytical model was validated with experimental results for different stacking sequences. Additionally, effect of fiber orientation on damage shape at below ballistic limit velocity was also studied.

The Behaviour of Fibre-Metal Laminates under High Velocity Impact Loading with Different Stacking Sequences of Al Alloy

2012 ◽  
Vol 225 ◽  
pp. 213-218 ◽  
Author(s):  
A.A. Ramadhan ◽  
Abdul Rahim Abu Talib ◽  
Azmin Shakrine Mohd Rafie ◽  
R. Zahari
Keyword(s):  
Impact Loading ◽  
High Velocity ◽  
Stacking Sequence ◽  
Ballistic Limit ◽  
High Velocity Impact ◽  
Velocity Impact ◽  
Limit Velocity ◽  
Fibre Metal ◽  
Ballistic Limit Velocity ◽  
The Impact

The high velocity impact response of composite laminated plates has been experimentally investigated using a nitrogen gas gun. Tests were undertaken on fibre-metal laminate (FML) structures based on Kevlar-29 fiber/epoxy-Alumina resin with different stacking sequences of 6061-T6 Al plates. Impact testing was conducted using a cylindrical shape of 7.62 mm diameter steel projectile at 400m/s velocity, which was investigated to achieve complete perforation of the target. The numerical parametric study of ballistic impacts caused by similar conditions in experimental work is undertaken to predict the ballistic limit velocity, energy absorbed by the target, and comparisons between simulations by using ANSYS AUTODYN 3D v.12.1 software and experimental work to study the effects of the shape of the projectile with different (4, 8, 12, 16 and 20mm) thicknesses on the ballistic limit velocity. While only one thickness was used with 24mm of back stacking sequence, it was not penetrated. The sequence of the Al plate position (front, middle and back) inside laminate plates of the composite specimen was also studied. The Al back stacking sequence plate for the overall results obtained was the optimum structure to resist the impact loading. The simulation results obtained of the residual velocity hereby are in good agreement with the experimental results with an average error of 1.8%. The energy absorption was obtained with 7.3% and 2.7% of the back to front and back to middle of the Al stacking sequence respectively. Hence, the back Al stacking sequence is considered the optimum position for resisting the impact loading. The data showed that these novel sandwich structures exhibit excellent energy-absorbing characteristics under high-velocity impact loading conditions. Hence, it is considered suitable for aerospace applications.

Specimen Thickness and Impactor Mass Effects on Drop-Weight Impact Studies of GLARE 5 Fiber-Metal Laminates

2011 ◽  
Author(s):  
A. Seyed Yaghoubi ◽  
B. Liaw
Keyword(s):  
Impact Velocity ◽  
Volume Fraction ◽  
Energy Condition ◽  
Specimen Thickness ◽  
Fiber Metal Laminates ◽  
Drop Weight ◽  
Metal Volume ◽  
Fiber Metal ◽  
The Impact ◽  
Metal Volume Fraction

Impact responses and damage induced by a drop-weight instrument on GLARE 5 fiber-metal laminates (FMLs) with different thicknesses were studied. The effect of impactor mass was also considered. The damage characteristics were evaluated using both nondestructive ultrasonic and mechanical sectioning techniques. The ultrasonic C-scan technique could only assess the contour of entire damage area whereas more details of damage were obtained using the mechanical cross-sectioning technique. As expected, thicker GLARE 5 FMLs offered higher impact resistance. When subjected to the same impact energy, the entire damage contour enlarged as the specimen became thicker. Under the same impact condition, by reducing the impactor mass, the contact force escalated while the contact stiffness increased. Experimental results showed that the threshold cracking energy varied parabolically with respect to the impact velocity, metal volume fraction (MVF) and the specimen thickness. By increasing the metal volume fraction of the panels, the threshold cracking energy decreased parabolically. On the other hand, for the same MVF value, the cracking energy increased as the impactor mass increased. By increasing the panel thickness, the threshold cracking energy condition increased parabolically; whereas under the same impact velocity, the threshold cracking energy increased by increasing the impactor mass.

scholarly journals Ballistic Limit Estimation Approaches for Ballistic Resistance Assessment

2020 ◽  
Vol 70 (1) ◽  
pp. 82-89
Author(s):  
Beya Tahenti ◽  
Frederik Coghe ◽  
Rachid Nasri
Keyword(s):  
Extreme Values ◽  
Impact Testing ◽  
Estimation Methods ◽  
Experimental Sample ◽  
Ballistic Limit ◽  
Ballistic Resistance ◽  
Limit Velocity ◽  
Resistance Assessment ◽  
Ballistic Limit Velocity ◽  
Set Up

The armour technologist conducts ballistic impact testing either for evaluating armour materials and systems or for studying material’s defeating mechanism. Most standards make use of the ballistic limit velocity for ballistic assessment. This is the bullet impact velocity that leads to the protection perforation in 50 per cent of the cases. Various models have been emerged to estimate this key metric. The present article summarises the popular models developed for ballistic limit estimation. An attempt is made to point out models’ strength and weakness. First, the experimental set-up used for that goal is displayed. Next, a concise overview of ballistic limit estimation methods is presented. Lastly, a discussion is dedicated to model’s comparison and analysis. This literature survey reveals that the main drawback of already existing methods is that they are purely statistical. Moreover, existing methods are based on the normality assumption of perforation velocities which tends from -infinity to infinity. The main conclusion of this survey is that the presented methods offer a comparable accuracy in estimating the ballistic limit velocity. However, a given variability is remarked when extreme values estimation is of interest, impact velocities leading to low and high perforation probability. Finally, existing models’ performances decay with the reduction of the experimental sample size which represent a constraining requirement in ballistic resistance assessment.

A Predictive Non-Dimensional Scaling Law for the Plate Perforation of Several Aluminum Alloys by Fragment-Simulating Projectiles

2019 ◽  
Author(s):  
Weinong Chen ◽  
Zherui Guo
Keyword(s):  
Aluminum Alloys ◽  
Scaling Law ◽  
Limit Equation ◽  
Ballistic Limit ◽  
Limit Velocity ◽  
Dimensional Scaling ◽  
Material Problem ◽  
Plate Perforation ◽  
Ballistic Limit Velocity ◽  
Aluminum Armor Plates

Abstract An equation was previously-presented to predict the ballistic-limit velocity for the perforation of aluminum armor plates by fragment-simulating projectiles (FSP). The ballistic-limit equation was presented in terms of dimensionless parameters so that the geometric and material problem scales are identified. Previously published predictions and data for two different FSP projectile calibers (12.7 mm and 20 mm) and two different strength aluminum alloys show the scaling law to be accurate. In this paper we extend the same concept to several other alloys and show that this scaling law is predictive.

scholarly journals Ballistic limit velocity of tungsten alloy spherical fragment penetrating Ti/Al3Ti-laminated composite target plates

2020 ◽  
Vol 29 ◽  
pp. 2633366X2092224 ◽  
Author(s):  
Yingbin Liu ◽  
Chufan Yin ◽  
Xiaoyan Hu ◽  
Meini Yuan
Keyword(s):  
Similarity Theory ◽  
Laminated Composite ◽  
Tungsten Alloy ◽  
Target Area ◽  
Ballistic Limit ◽  
Composite Target ◽  
Area Density ◽  
Limit Velocity ◽  
Ballistic Limit Velocity ◽  
Different Thickness

To determine the ballistic limit velocity of titanium–titanium tri-aluminide (Ti/Al3Ti)-laminated composites under the action of tungsten alloy spherical fragments, a type of 12.7 mm ballistic gun loading system was used to test the tungsten alloy spherical fragments vertically impacting the Ti/Al3Ti-laminated composite targets with different thickness. The relationship between the ballistic limit velocity and the target area density of the Ti/Al3Ti-laminated composite was obtained. As the area density increased, the ballistic limit velocity and the ballistic energy absorbed by the target plate also enhanced. Based on the dimensional analysis and similarity theory, a simulation law of tungsten alloy spherical fragments penetrating Ti/Al3Ti-laminated composite targets with different thickness was studied and an empirical formula for the ballistic limit velocity was obtained. The research results had an important application value for the optimal design of the light armor protection structure.

The Numerical Method as Applied to Impact Resistance Analysis of Ogival Nose Projectiles on 6061-T651 Aluminum Plates

2012 ◽  
Vol 28 (4) ◽  
pp. 715-726 ◽  
Author(s):  
Y.-L. Chen ◽  
H.-C. Chen
Keyword(s):  
Numerical Method ◽  
Predictive Model ◽  
Penetration Depth ◽  
High Speed ◽  
Ballistic Limit ◽  
Residual Velocity ◽  
Finite Element Software ◽  
Limit Velocity ◽  
Aluminum Plates ◽  
Ballistic Limit Velocity

ABSTRACTThis research takes the resistance formula of spherical cavity expansion theory as its foundation. It establishes a predictive model of the residual velocity, ballistic limit velocity, and penetration depth of ogival nose projectiles striking metal target plates at high speed. They are aimed at 6061-T651 aluminum plates of different thicknesses using the iterative algorithm of the numerical method, thereby investigating the theoretical calculation of the residual velocity, penetration depth, ballistic limit velocity, and changes in resistance of ogival nose projectiles when making a normal impact target. In addition to analyzing the resistance undergone by the projectile nose section, this predictive model also considers the effects of friction resistance of the projectile shank section. In this research, we also used the finite element software LS-DYNA to perform a simulated analysis on the penetration depth of the aluminum plate after normal perforation by ogival nose projectiles. Ballistic test experiments were then performed using 0.30” AP (armor piercing) bullets. Finally, a comparative analysis was performed based on the theoretical model, experiments, and numerical simulation results.

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