Experimental validation of BLV model on bi-layer ceramic-metal armor (original) (raw)
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Ballistic impact on bi-layer alumina/aluminium armor: A semi-analytical approach
International Journal of Impact Engineering, 2013
This paper presents a semi-analytical approach on the performance of ceramic/metal armor under ballistic impact. Numerical simulations for alumina/aluminum armor impacted by 20 mm APDS in AUTODYN were carried out and verified against the experimental data. Comprehensive numerical simulations were performed using the verified numerical model material parameters providing corroborative data for ensuing discussions. A semi-analytical model relating projectile residual velocity, impact velocity and armor ballistic limit velocity (BLV) is presented for impact of hard projectile against ceramic/metal armor. It is shown that the projectile residual velocity and BLV satisfy the replica scaling laws. Based on the replica scaling laws of projectile residual velocity and BLV, an empirical equation for BLV is obtained and used for armor optimization applications giving reasonable results similar to experiments available in the literature.
Ballistic Impact Simulation of Ceramic/Metal Armor Structures
Uluslararası Muhendislik Arastirma ve Gelistirme Dergisi, 2017
The study presents a comparative numerical investigation on ballistic performance of ceramic/metal armor structures. 2D axisymmetric numerical model was developed for ballistic impact simulations using LS-DYNA ® finite element software. The armor structures included combinations of boron carbide (B4C), Al6061-T6 and 4340 steel constituents. The interfaces in the armor structure were modelled with an epoxy resin adhesive. In order to define proper material behavior, Johnson-Holmquist-Ceramics material model for B4C and Plastic-Kinematic material model for Al6061-T6, 4340 steel and epoxy resin was used. The armor structures were subjected to 7.62 mm ogive-nosed steel projectile impact. In the first section, the influence of back plate material on the ballistic performance of the armor structure for bi-layers ceramic/metal configuration (ceramic front face and metal back plate) was investigated for Al6061-T6 and 4340 steel materials under same thickness and areal density. In the second section, the effect of removing half thickness of the metal constituent from the back plate and placing on the front face was investigated for both Al6061-T6 and 4340 steel materials. Finally, the influence of adhesive thickness on the ballistic performance of the armor structure was investigated. Perforation response of the armor structures were examined in terms of residual velocity of the projectile and damage mechanisms of the armor structure.
Numerical Simulation of Ballistic Impact on Ceramic Armor
Proceedings of the 4th …, 2006
A preliminary investigation of ballistic impact on ceramic armor was carried out by recourse to numerical simulation using finite element method. Following our earlier study [1] on the effect of stress wave propagation from dynamic loads, the current computational model was developed with built-in brittle failure criteria, aiming to correlate with experimental ballistic testing. It was found that the rate that the ceramic armor absorbed the bullet kinetic energy raised as the armor thickness increased.
Analysis and investigation of ballistic impact on ceramic/metal composite armour
International Journal of Machine Tools and Manufacture, 2004
The subject of this paper is to analyze the impact of projectiles against ceramic/metal armour using a simple one-dimensional mode. The model allows the calculation of the loss of projectile mass and its velocity, and gives the deflection of the backup material. This work also investigates the influence of grain size of the ceramic material on ballistic performance, which is very useful during selection of the best material for each application. Therefore, two formulations of the same ceramic material were produced. They had the same chemical composition, the same mechanical properties, but different grain size. The ballistic performances were compared measuring the maximum velocity each formulation was able to support, without perforation.
Finite element simulation of ceramic/composite armor under ballistic impact
Composites Part B: Engineering, 2011
In this paper, based on LS-Dyna code, a new finite element (FE) simulation of the ballistic perforation of the ceramic/composite targets, which impacted by cylindrical tungsten projectiles, has been presented. Research on this method has been conducted by a few research groups in recent years. The ceramic material, which is the front plate, has been made of Alumina 99.5% and composite backup plate composed of Twaron fibers. The 2-dimensional (2D), axi-symmetric, dynamic-explicit, Lagrangian model has been considered in this simulation. The Johnson-Cook, Johnson-Holmquist and Composite-Damage materials behaviors have been used for projectile, ceramic and composite materials respectively. The brittle fracture and fragmentation of ceramic conoid, the failure criteria based on fracture of fibers or matrixes of composite materials and erosion or flattening of projectile during perforation have been considered. The residual velocity and perforation time has been obtained and compared with the available analytical models. The results show that when the ceramic is impacted by a projectile, a fragmented ceramic conoid breaks from ceramic tile and the semi-angle of ceramic conoid with increasing initial velocity decreases. Furthermore, the dishing of composite layers at high impact velocities and the delamination of layers near the ballistic limit velocity decrease.
Numerical Simulations of Level 3A Ballistic Impact on Ceramic/Steel Armor
Proceedings of the …, 2006
This article concerns with the ABAQUS simulation of 9-mm-bullet impacts with initial velocities between 419 -431 m/s on ceramic/steel armor plates, which complies with the level 3A of the National Institute of Justice (NIJ) standard. In most studies, the impactators are very hard compared to the armor. In reality, the bullets are quite soft and frequently disintegrate upon impacts, making them particularly difficult to model. This preliminary study aims to confirm that the relative strength of the bullet and armor is a major aspect in the ballistic simulations. Without trying to accurately capture the bullet rupture, pragmatic numerical models may be obtained by using hard bullets and armor plates with heightened strengths. That is, the bullet is elastic while the strength of ceramic armor, whose function is to shatter the bullet, is raised by increasing the tensile strength. It can be argued that rough simulations of impacts may be obtained and numerical results of 4 simulations, in which the tensile strength of ceramics are heightened, qualitatively agree with the experimental observations.
Structures Under Shock and Impact X, 2008
In this study, perforation performance tests of multi layered ceramic-metal composite armours consisting of alumina ceramics (99.5% Al 2 O 3) and aluminium Al 2024-T351 backup materials against a 7.62mm armour piercing (AP) bullet and a 12.7mm AP bullet impact were numerically simulated and then these simulations were verified by the ballistic tests. Nonlinear dynamics finite element simulations are solved with the LS-DYNA lagrangian solver. In the study, new sets of material constants for appropriate material models, which describe the bullet's steel core and aluminium target material deformation better, are obtained. These new material constants are obtained by evaluating stress-strain curve data and also making Depth of Penetration (DOP) simulations and verification tests for each AP bullet and Al 2024-T351 material before perforation performance simulations of ceramic composite structures. The 3D finite element model is generated and compared with 2D simulations. For DOP simulations, the steel core of the bullet is only modelled, but for perforation simulations a full bullet (copper jacketed and filler material) model is used in simulations for the 12.7mm AP bullet. According to the DOP simulation results, Plastic-Kinematics hardening material model is reasonable enough to describe material damage modelling for both bullets and Al 2024-T351 material. Failure strain (FS), which is the most critical value in the simulations, is obtained from stress-strain curve data and also evaluating DOP test results with some correlation for high strain rate condition. The FS value for Al 2024-T351 against a 12.7mm bullet impact is estimated higher than a 7.62mm bullet impact, which is well expressed by strain hardening due to the increased impact area and energy of the bullet. In perforation simulations, bullets and Al 2024-T351 are simulated with a plastic-kinematics hardening material model, but for the ceramics material, a Johnson-Holmquist (JH2) ceramic material model is selected for a good estimation. Ballistic verification tests performed show that numerical simulations are overlapped successfully with the test results with an acceptable difference. With these appropriate material model constants; the fracture conoid in ceramics, bullet deviation from the line of impact and then stopping, bullet end deformation and aluminium bulging is well shown in the simulations.
Numerical modelling of normal impact on ceramic composite armours
International Journal of Impact Engineering, 1992
In thas paper, the penetration of ceramic targets backed by thm metallic plates when impacted by cylindrical projectiles is studied. To achieve this, a two-dimensional axisymmetric numerical analysis of the normal impact problem is performed. The macroscopic material behavlour in the zone of finely pulverized ceramic ahead of the penetrator is modelled by means of a constitutive model taking into account internal friction and volumetric expansion. The amount of comminutlon at the computational cells is evaluated through a damage evolution equation, and the yield stress is assumed to be a function of the hydrostatic pressure, internal friction and amount of comminutlon. For the metallic materials involved, an elasto-plastic behaviour with a rupture condition was considered. Moreover, an erosion condition was included as a limit situation when the ruptured material limits its role m the penetration process to purely inertial effects. In this way, a detailed picture of the penetration process of the target by the impacting projectile was obtained. Then, the results of the numerical analysis were compared with the experimental observations of the projectde-target interaction, previously made by Reijer by usmg a flash X-ray technique. Under certain conditions, remarkable agreement between computations and experiments is encountered, thus suggesting the adequacy of the main assumptions made in the numerical approach to the physical situation.
Modelling of Fracture Processes in the Ballistic Impact on Ceramic Armours
Journal De Physique Iv, 1997
This work examines the essential physical processes in the perforation of metal backed ceramic annours which include projectile erosion, fracture of the ceramic tile and ductile deformation of the metal backing plate. The impact of projectiles onto alumina and aluminium nitride ceramic materials is studied experimentally and numerically. Observations were performed using an X-ray shadowgraph technique to obtain accurate data of the penetration process at different times. From the examination of computer simulations and corresponding impact experiments a simple at~ulyficul rrlodcl is developed by assuming some hypotheses simplifying the actual mechanisms of the penetration process. Material description is simplified by using simple equations and a few material parameters easily obtained experimentally, such as the elastic modulus, the compressive and tensile strength and the rupture strain. Rburnk Ce travail examine les procts physiques essentiels qui concernent la perforation des bIindages ctramiquelrnttal en incluant dans un modble analytique I'trosion du projectile, la fracture de la cdramique et la d6formation plastique de la plaque 1n6tallique. L'impact dc projectiles sur des plaques d'oxide d'aluminium et de nihure d'aluminium est ttudii expirimentale et numtriquement. Pour obtenir les donnts expirimentales un appareil photographique A rayons X a 616 utilist, permettant observer avec prtcision le procts de pddtration. A partir de I'analyse des simulations numtriques et des donntes exp6rimentales un modtle analytique a ttd dkveloppt en assumant une grande simplification des micanismes de perforation. Le comportement mdcanique des mattriaux est simplifit en faisant appel B des equations constitutives simples avec quelques parantktres facilement accessibles exptrimentalement comme le module d'tlasticit6, la rtsistance A compression et la dtformation maximale. 1. Sketch of a typical cerarniclaluminium armour.
Numerical simulation of ceramic composite armor subjected to ballistic impact
Composites Part B-engineering
Armor systems made of ceramic and composite materials are widely used in ballistic applications to defeat armor piercing (AP) projectiles. Both the designers and users of body armor face interesting choices -how best to balance the competing requirements posed by weight, thickness and cost of the armor package for a particular threat level. A finite element model with a well developed material model is indispensible in understanding the various nuances of projectile-armor interaction and finding effective ways of developing lightweight solutions. In this research we use the explicit finite element analysis and explain how the models are built and the results verified. The Johnson-Holmquist material model in LS-DYNA is used to model the impact phenomenon in ceramic material. A user defined material model is developed to characterize the ductile backing made of ultra high molecular weight polyethylene (UHMWPE) material. An ad hoc design optimization is carried out to design a thin, light and cost-effective armor package. Laboratory testing of the prototype package shows that the finite element predictions of damage are excellent though the back face deformations are under predicted.