scholarly journals Influence of Add-On Perforated Plates on the Protective Performance of Light-Weight Armour Systems

2018 ◽  
Vol 9 (1) ◽  
pp. 31-48
Author(s):  
Teresa FRAS ◽  
Norbert FADERL
Keyword(s):  
Hard Core ◽  
High Hardness ◽  
Steel Plates ◽  
Perforated Plates ◽  
Geometrical Properties ◽  
Impact Position ◽  
Circular Holes ◽  
Protective Performance ◽  
The Impact ◽  
Armour Steel

The presented experimental investigation, aimed at verification of defeat mechanisms against small-calibre projectiles, provided by 4-mm-thick perforated plates with different material- and geometrical properties, was performed. A regular pattern of punched holes in steel plates increases the possibility of asymmetrical contact between the plate and projectiles which may cause threat destabilization, rotation or fragmentation depending on the impact position. Three tested armour configurations comprise the super-bainitic high-hardness Pavise™ SBS 600P armour steel plates perforated by elongated holes of size 4  12 mm (the first configuration), the martensitic high-hardness Mars® 300P steel plates perforated by circular holes with a diameter of 5 mm (in the second configuration); and in the third configuration, the martensitic Mars® 300 plates perforated by oblong holes (4  10 mm) were used. The performed impact tests proved that the tested add-on plates assured high protection against the impact of 7.62  51 .308 Win P80 hard-core armour piercing (AP) projectiles. It was also observed that the plates caused similar mechanisms of bullet failure.

Modelling the Fracture of High-Hardness Armour Steel in Taylor Rod-on-Anvil Experiments

2019 ◽  
Author(s):  
Brodie McDonald ◽  
Shannon Ryan ◽  
Stephen J. Cimpoeru ◽  
Nathan Edwards ◽  
Adrian Orifici
Keyword(s):  
Shear Band ◽  
Impact Velocity ◽  
Numerical Models ◽  
Computational Cost ◽  
Stress Triaxiality ◽  
High Hardness ◽  
Material Strength ◽  
Fracture Threshold ◽  
The Impact ◽  
Armour Steel

Abstract A series of Taylor rod-on-anvil experiments have been performed to validate the predicted impact velocity fracture threshold and fracture mode of a high hardness armour steel (HHA) obtained through explicit finite element simulations. Experimentally, the rods exhibited principal shear failure, a condition that can be closely linked to adiabatic shear band (ASB) formation in high strength steel. Using a stress triaxiality and Lode angle dependent failure strain criterion (Basaran 3D fracture locus), calibrated from quasi-static mechanical characterisation tests, the simulations were unable to predict the onset of fracture observed in experiments. As such, a strength-fading criterion is proposed using a phenomenological description to capture the loss of load-carrying capacity resulting from ASB formation. The ASB criterion is based on an exponential fit to experimentally-observed instability strains measured at different average stress triaxialities in a series of tests on inclined cylindrical and modified flat-hat specimens. With the prediction of ASB formation the material strength is reduced to model the thermal softening experienced in the shear band, and fracture of the material (in the form of element erosion) remains controlled by the Basaran fracture model. Incorporating the ASB-based criterion, the numerical models were found to accurately predict both the impact velocity fracture threshold, as well as the general appearance of the observed principal shear fracture. The proposed criterion enables the effects of ASB formation to be captured in an impact simulation with little increase in computational cost.

scholarly journals Selected Issues of Increasing the Fire Effectiveness of Combat Vehicles

2020 ◽  
Vol 50 (3) ◽  
pp. 417-438
Author(s):  
Rafał Bazela
Keyword(s):  
Numerical Analysis ◽  
Penetration Depth ◽  
Research Paper ◽  
Performance Characteristics ◽  
Steel Plates ◽  
Current State ◽  
Vehicle Technology ◽  
The Impact ◽  
Armour Steel

AbstractThe research paper reviews selected issues associated with the current state of the armoured (tanks) and infantry fighting vehicle technology, with particular emphasis on the operating effectiveness of elongated sub-calibre projectiles fired from tank guns, which enable full perforation of ca. 500 mm thick armour steel plates. Their efficiency is comparable with the impact of shaped heads with armour steel penetration capabilities, and amounts from 6 to 8 calibres – warhead diameters. Furthermore, the paper discusses a numerical analysis, which shows the velocities of elongated projectiles (of tungsten matrix sinters) required to achieve a determined armour steel penetration depth. In addition, it also presents the performance characteristics of two 100 mm calibre shaped warheads, with copper inserts and apex angles of 51º and 60º.

scholarly journals High-Velocity Impacts of Pyrophoric Alloy Fragments on Thin Armour Steel Plates

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4649
Author(s):  
Evaristo Santamaria Ferraro ◽  
Marina Seidl ◽  
Tom De Vuyst ◽  
Norbert Faderl
Keyword(s):  
High Velocity ◽  
High Speed ◽  
Failure Modes ◽  
Threshold Value ◽  
Steel Plates ◽  
Terminal Ballistics ◽  
High Velocity Impacts ◽  
Modern Warfare ◽  
The Impact ◽  
Armour Steel

The terminal ballistics effects of Intermetallic Reactive Materials (IRM) fragments have been the object of intense research in recent years. IRM fragments flying at velocities up to 2000 m/s represent a realistic threat in modern warfare scenarios as these materials are substituting conventional solutions in defense applications. The IRM add Impact Induced Energy Release (IIER) to the mechanical interaction with a target. Therefore, the necessity of investigations on IIER to quantify potential threats to existing protection systems. In this study, Mixed Rare Earths (MRE) fragments were used due to the mechanical and pyrophoric affinity with IRM, the commercial availability and cost-effectiveness. High-Velocity Impacts (HVI) of MRE were performed at velocities ranging from 800 to 1600 m/s and recorded using a high-speed camera. 70 MREs cylindrical fragments and 24 steel fragments were shot on armour steel plates with thicknesses ranging from 2 mm to 3 mm. The influence of the impact pitch angle (α) on HVI outcomes was assessed, defining a threshold value at α of 20°. The influence of the failure modes of MRE and steel fragments on the critical impact velocities (CIV) and critical kinetic energy (Ekin crit) was evaluated. An energy-based model was developed and fitted with sufficient accuracy the Normalised EKin crit (E˜kincrit) determined from the experiments. IIER was observed in all the experiments involving MRE. From the analyses, it was observed that the IIER spreads behind the targets with velocities comparable to the residual velocities of plugs and shattered fragment.

scholarly journals Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Yamada ◽  
Kohei Tateyama ◽  
Shino Naruke ◽  
Hisashi Sasaki ◽  
Shinichi Torigata ◽  
...  
Keyword(s):  
Impact Energy ◽  
Impact Test ◽  
Impact Resistance ◽  
Protective Layer ◽  
High Strength ◽  
Steel Plates ◽  
Corrugated Plates ◽  
Shelter Construction ◽  
The Impact ◽  
Ballistic Ejecta

AbstractThe destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

Elastic Design Methods for Perforated Plates

1978 ◽  
Vol 100 (2) ◽  
pp. 356-362 ◽  
Author(s):  
J. S. Porowski ◽  
W. J. O’Donnell
Keyword(s):  
Finite Element ◽  
Thermal Loading ◽  
Solid Material ◽  
Perforated Plates ◽  
Finite Element Stress Analysis ◽  
Effective Elastic Constants ◽  
New Methods ◽  
Circular Holes ◽  
Elastic Design ◽  
Generalized Plane Strain

Methods for performing finite element stress analysis of perforated plates under pressure and complex thermal loading conditions are described. The concept of the equivalent solid material of anisotropic properties is employed to define the elasticity matrices to be used for axisymmetric analysis of plates containing triangular and square patterns of circular holes. Generalized plane strain effective elastic constants are used for better approximation of the overall plate behavior. New methods and curves for obtaining local ligament stresses from the nominal stresses in the equivalent solid material are given.

Tribological characteristics of AA8090-WC-ZrC metal matrix composites prepared by stir casting process for Aerospace applications

2021 ◽  
Vol 73 (6) ◽  
pp. 980-985
Author(s):  
Kalaiyarasan A ◽  
Sundaram S ◽  
Gunasekaran K ◽  
Bensam Raj J.
Keyword(s):  
Metal Matrix ◽  
Materials Science ◽  
Scientific Information ◽  
High Hardness ◽  
Hardness Test ◽  
Casting Process ◽  
Stir Casting ◽  
Hybrid Particles ◽  
Content Type ◽  
The Impact

Purpose Aerospace field is demanding a material with superior strength and high resistance against wear, tear and corrosion. The current study aimed to develop a new material with high performance to be applicable in aerospace field Design/methodology/approach A metal matrix composite AA8090-WC-ZrC was fabricated using stir casting method and its tribological behavior was investigated. Totally, five composites viz. AA/Z, AA/W, AA/WZ (1:3), AA/WZ (1:1) & AA/WZ (3:1) were prepared. Micro hardness, tensile and wear study were performed on the fabricated composites and the results were compared with AA8090 alloy Findings Vickers hardness test resulted that the AA/W composite showed the higher hardness value of 160 HB compared to other materials due to the reinforcing effect of WC particles with high hardness. Tensile test reported that the AA/W composite displayed the maximum tensile strength of 502 MPa owing to the creation of more dislocation density. Further, wear study showed that the AA/W composite exhibited the least wear rate of 0.0011 mm3/m because of the more resisting force offered by the WC particles. Furthermore, the AA/W composite showed the slightest mass loss of 0.0028 g and lower COF value of 0.31 due to the hinder effect of WC particle to the movement of atoms in AA8090 alloy Originality/value This work is original in the field of aerospace engineering and materials science which deals with the fabrication of AA8090 alloy with the reinforcement particles such as tungsten carbide and zirconium carbide. The impact of the combination of hybrid particles and their volume fractions on the tribological properties has been investigated in this work. This work would provide new scientific information to society.

scholarly journals The Contact Mechanics of Novikov’s Surface-Hardened Gearing during Running-in Process

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Alexey Beskopylny ◽  
Nikolay Onishkov ◽  
Viktor Korotkin
Keyword(s):  
Cold Deformation ◽  
Contact Fatigue ◽  
High Hardness ◽  
Contact Spot ◽  
The State ◽  
Contact Strength ◽  
Friction Forces ◽  
Contact Surfaces ◽  
Defective Surface ◽  
The Impact

The article is devoted to the analysis of the state of the contact surfaces of the higher kinematic pair in the general case of relative motion, that is, in the presence of rolling, sliding, and twisting, which is characteristic of Novikov’s circular-screw gears. The purpose of the work is to assess the impact of friction forces, the state of contact surfaces after tool processing, and the localization of the instantaneous contact spot on the level of contact—fatigue durability of gears. Power contact in the presence of geometric slippage of the mating surfaces leads to a significant change in the initial geometry and the mechanical properties of surface layers. In the existing methods of calculations of contact strength, the effect of running-in is investigated insufficiently, which leads to an incorrect result, especially for gear with high hardness of the teeth. In this work, the conditions of contact interaction close to the real requirements are studied on the basis of experimental material, numerical solution of the contact problem, determination of the terms of the contact areas of slip, and adhesion within the instantaneous spot. The shape of the instant contact spot has asymmetry and can be approximated by an ellipse with the introduction of a correction factor. The running-in period is of a plastic nature with cold deformation and reduction of the roughness of surfaces. As a result of the run-in period, the area of actual contact (tooth height) is increased by 2 or more times. It is not desirable to spread the area of contact at the area of adhesion that initiates the formation of pitting. The presence of defective surface area on the level of contact strength does not have significant influence, because of the running-in period, but increases the risk of spalling and brittle fracture.

scholarly journals Analysis of Errors in the Estimation of Impact Positions in Plate-Like Structure through the Triangulation Formula by Piezoelectric Sensors Monitoring

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3426 ◽  
Author(s):  
Eugenio Marino-Merlo ◽  
Andrea Bulletti ◽  
Pietro Giannelli ◽  
Marco Calzolai ◽  
Lorenzo Capineri
Keyword(s):  
Propagation Velocity ◽  
Lamb Waves ◽  
Correlation Method ◽  
Time Of Arrival ◽  
Impact Point ◽  
Laboratory Procedure ◽  
Impact Position ◽  
Set Up ◽  
Two Parameters ◽  
The Impact

The structural health monitoring (SHM) of critical structures is a complex task that involves the use of different sensors that are also aimed at the identification of the location of the impact point using ultrasonic sensors. For the evaluation of the impact position, reference is often made to the well-known triangulation method. This method requires the estimation of the differential time of arrival (DToA) and the group velocity of the Lamb waves propagating into a plate-like structure: the uncertainty of these two parameters is taken into consideration as main cause of localization error. The work proposes a simple laboratory procedure based on a set-up with a pair of sensors that are symmetrically placed with respect to the impact point, to estimate the uncertainty of the DToA and the propagation velocity estimates. According to a theoretical analysis of the error for the impact position, the experimental uncertainties of DToA and the propagation velocity are used to estimate the overall limit of the SHM system for the impact positioning. Because the error for the DToA estimate depends also on the adopted signal processing, three common methods are selected and compared: the threshold, the correlation method, and a likelihood algorithm. Finally, the analysis of the positioning error using multisensory configuration is reported as useful for the design of the SHM system.

Ballistic response of 12.7 mm armour piercing projectile against perforated armour developed from structural steel

2018 ◽  
Vol 233 (10) ◽  
pp. 1993-2005
Author(s):  
A Mubashar ◽  
Emad Uddin ◽  
S Anwar ◽  
N Arif ◽  
S Waheed Ul Haq ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Structural Steel ◽  
Perforated Plate ◽  
High Hardness ◽  
The Core ◽  
Numerical Studies ◽  
Ballistic Protection ◽  
Asymmetric Impact ◽  
Impact Side ◽  
The Impact

This study investigates ballistic response of a developed perforated armour plate against 12.7 mm armour piercing tracer projectile. Experimental as well as numerical studies were carried out and the penetration of the projectile through a base aluminium plate was determined with and without the perforated armour plate. The armour piercing projectiles were able to penetrate the base armour plate in successive impacts. However, the combination of the perforated and base armour plates was able to stop the penetration of the armour piercing projectile. A finite element method-based numerical model was developed to investigate the defeating phenomenon of perforated and base armour plate combination. It was observed that the asymmetric impact of the projectile core did not produce large enough bending to fracture the core. However, the high hardness of the developed perforated plate was able to shatter the projectile core in multiple fragments which were then unable to penetrate the base armour plate. Craters of varying depths were observed on the impact side of the base armour plate. The research showed that the selected structural steel can be successfully used for ballistic protection.

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