Target Plate Thickness Research Articles

Analysis of bullet impact test on aluminum alloy plates at varying thickness and velocities

Analysis of bullet impact test on aluminum alloy plates at varying thickness and velocities

Research on the high-speed impact of projectiles on reinforced concrete equivalent targets

Due to the prolonged production cycle of reinforced concrete target plates and the need for a series of preparations and tests before use, it is essential to study the equivalent relationship between reinforced concrete target plates and steel target plates. Numerical simulations of the process of projectiles vertically penetrating reinforced concrete target plates were conducted using LS-DYNA software. Models for both reinforced concrete and steel targets were established, and the equivalent thickness conversion relationship between the two was obtained. Simulation results indicated an inverse proportional relationship between projectile residual kinetic energy and target thickness. Curve fitting using Origin software was performed to obtain the conversion relationship between the thicknesses of reinforced concrete target plates and steel targets. The simulation results were validated, showing an error in concrete target plate thickness conversion of less than 10%. The research results provide theoretical support and data references for the equivalent study of reinforced concrete target plates and steel target plates.

A numerical ballistic performance investigation of Armox 500T steel through ductile damage models

In this work, the ballistic response of an armor steel, Armox 500T, is numerically investigated through finite element (FE) analysis by utilizing the Johnson–Cook (JC) and modified Mohr–Coulomb (MMC) damage models, with a focus on emphasizing the consequences of different modeling approaches. Although Lode-dependent failure models are considered to increase the accuracy of numerical predictions for ductile failure, there remains a complete lack of clarity as to whether all conditions and materials necessitate the adoption of such models for ballistic impact simulations. In this context, MMC and JC model parameters are calibrated through tensile test data available in the literature enabling direct comparison between them. Damage models are then validated using ballistic impact tests of Armox 500T performed with 7.62 API projectiles. The results indicate that the MMC model outperforms the JC model at predicting the failure modes while both models demonstrate strong performance in anticipating the residual velocity. The influence of projectile nose shape, target plate thickness, and impact angle are further investigated, and the effect of incorporating the Lode parameter is discussed in detail. Impact simulations with the blunt projectile nose shape is found to be highly sensitive to the effect of Lode angle on failure, with differences of up to 20% between models, while 7.62 API shows the lowest sensitivity. The difference between the models’ predictions is observed to increase at lower impact velocities and higher impact angles demonstrating the necessity of a Lode-dependent failure model for such cases. The JC model consistently yields smaller residual velocities compared to the MMC model in all cases indicating that the MMC is more conservative in terms of predicting protective performance of Armox 500T.

ZK61m magnesium alloy plate thickness effect on the impact characteristics of blunt projectiles experimental and numerical simulation studies

To study the impact resistance of ZK61m magnesium alloy plate, firstly, impact experiments were conducted on magnesium alloy plates of different thicknesses using a one-stage gas gun system to obtain the ballistic limit velocity (BLV) and failure mode of the target plate. In addition, the velocity of the punch plug was analyzed by the squeeze chisel block velocity model. Finally, the corresponding numerical simulations were carried out using the Lode parameter-independent MJC fracture criterion and the Lode parameter-dependent MMC fracture criterion, and the influence mechanism of the Lode parameter on the numerical simulation results was analyzed. The results show that under the impact of the blunt projectile, different thicknesses of target plates mainly occur shear plug failure, the BLV first tends to flatten and then increases sharply with the increase of its thickness. Besides, in the same velocity interval, the plugging velocity decreases with the increase of the target plate thickness; the Lode parameter has an obvious influence on the simulation results, which the MMC fracture criterion is more consistent with the experimental results. However, with the increase of the target plate thickness, both MMC and MJC fracture criteria show the phenomenon of overestimation of the material ductility.

Compensation model for truncated ogive projectiles penetrating ship stiffened plates made from different materials

This paper establishes a new similarity method for the problem of truncated ogive projectiles penetrating ship plates. This method can consider plates made of different materials and summarizes the relationship between material strength and target plate thickness through an energy-based formulation and dimensional analysis. Using the finite element software DYNA, multiple sets of numerical simulations are carried out, and the power parameter of the target plate thickness is determined. Subsequently, the scope of the penetration problem is extended to the stiffened plate structure of a ship. When a stiffener is considered, the change in the attitude angle of the projectile is very important. The deflection of the projectile may lead to incomplete penetration of the target plate, or even cause the projectile to ricochet. The prototype response can be accurately predicted by compensating all structural dimensions of the stiffened plate according to the plate thickness correction parameters. On this basis, adjusting the ventral plate thickness of the stiffener effectively changes the trend in the attitude angle of the projectile. The errors in the residual velocity and attitude angle of the projectile are guaranteed to be within a reasonable range.

Material similarity law of blunt projectiles penetrating scaled steel target plates

This study aims to enable the use of target plates composed of different materials in the penetration problem through the H-method similarity framework. Since different fracture toughness can lead to imperfect similarity between models, the concepts of Volume-failure strain and Volume-yield stress are introduced, which can well describe the high-velocity penetration problem involving fracture toughness. To ensure that the initial velocity of the projectile does not change, the similarity distortion among scaled models composed of different materials and the prototype is compensated by changing the target plate thickness. The feasibility of the proposed method is preliminarily proven based on the analysis model of the dimensionless critical impact energy of the target plate and the residual velocity of the projectile during penetration. Moreover, numerical simulations of blunt projectiles penetrating steel plates are performed. By changing the target plate thickness, the similarity differences among scaled models composed of different materials are effectively resolved. The errors of the residual velocity and peak force are in a completely reasonable range.

Design and development of new spiral head projectiles undergoing ballistics impact

PurposeThe purpose of this study is to design and develop new spiral head projectiles undergoing ballistics impact.Design/methodology/approachThe introduction of the rifled barrel in firearms made projectile spin during its flight path. The central translational velocity (impact velocity) is one parameter to defeat/penetrate the target in the penetration process. Another important parameter considered to be the shape of the projectile. Many types of projectile shapes have been designed to defeat the target. In the recent years, ogival nose shape is one of the well-known projectile shapes in use abundantly. The present research is made to design the nose shape so as to use the spin during the penetration of target effectively. In this study, a new spiral head projectile shape is proposed and designed, which uses the rotation of projectile (spin) for penetrating the Al7075-T6 target. When the ogive and new spiral head projectile is impacted on Al 7075-T6 target of 12.5 mm, 18 mm thicknesses at ordnance velocities, the residual velocity is evaluated numerically using ANSYS/Explicit Dynamics at normal impact condition. Two projectile materials, steel 4340 and tungsten alloy, are used as projectile materials. Along with the translational velocity, rotation velocities (spin rate) 13,000, 26,000 and 52,000 rad/s also provided to projectile. The residual velocities verses spin rate are plotted for different spiral angle projectiles for impact velocities 1,000–1,500 m/s, at normal impact conditions on the Al 7075-T6 target. Compared with the ogive nose projectile, the proposed new spiral head projectile made of tungsten alloy is significantly effective.FindingsSpiral head projectile having tungsten alloy material gives encouraging results at 12.5 mm target thickness. The new spiral head projectile is damaged partially. At 18 mm target thickness impact conditions, it is observed that the projectile head is completely damaged. The effectiveness of spiral head projectile on a target plate thickness of 18 mm is considered to study the impact condition.Research limitations/implicationsAll the above results need to be experimentally verified. However, the basic numerical model used in the present study, i.e. the basic ogive nose numerical model with only translational energy, is well validated with penetration theory available in literatures.Practical implicationsThe designed new spiral head projectile is only effective with tungsten alloy material within considered design parameters. For steel 4340 material, the spiral head projectile is less effective than the ogive nose projectile. In tungsten alloy projectiles, by observing all considered spiral angles, 30-degree spiral angle projectile gives the best performance at most of the considered impact velocity conditions.Originality/valueThe proposed research outputs are original, innovative and, have lot of importance in defence applications particularly in arms and ammunitions.

Effects of spinning on residual velocity of ogive-nosed projectile undergoing ordnance velocity impact

In the present article, finite element analysis (FEA) based simulation on the study of the impact of projectiles having ogive nose shape has been made using ANSYS explicit dynamics. The effects of spinning on the residual velocity of ogive nosed projectile undergoing ordnance velocity impact have been presented. The variations of residual velocity due to different projectile materials and target plate thickness have been evaluated when the projectile is impacted by translational and spinning velocity. The target plates and ogive nosed projectile of a given material are discretized, and a rigorous error and convergence study has been made. Subsequently, the residual velocity of the considered model is evaluated by numerical techniques based on FEA. The results with the optimized meshed model are compared with the analytical results using the penetration theory and found that the results are well compared. Parametric study of the residual velocity has been made with varied ogive nosed materials and target plate thickness when the ogive nosed projectile undergoing ordnance velocity impact. Based on the numerical results, it has been found that the ogive nose projectile having tungsten alloy material is more effective undergoing ordnance velocity impact compared to steel 4340 material. For a given target plate thickness, spinning velocity, and impact velocity, the residual velocity is about 3 percent higher for the projectile made up of tungsten alloy compared to the steel 4340. The effects of the target plate thickness on the residual velocity of the ogive nose projectile do not seem to have much significant effects. It may be due to the simple reason that the ratio of the target plate thickness to projectile diameter is remaining within the intermediate range, i.e. within 1 and 10.

Changes of projectile attitude and its influence parameters during the process of penetration on the ship plate structure through material point method

In this paper, the attitude changes of projectile and its influence parameters during the process of penetration on the ship plate structure are studied by material point method. The method is firstly verified by comparing with experimental results. The numerical results agree well with the experimental results. The failure behavior of the plate is similar to the actual situation, and the failure mode is basically the same. With the change of different parameters, the attitude of projectiles will change differently. The greater the penetration velocity, the weaker the influence of other related parameters on the projectile attitude. When other parameters are not changed, the relative size of the strength of stiffener and the thickness of target plate determines the change of the projectile attitude. Analyze from the perspective of energy and force, and finally projectile attitude can be divided into four types.

Experimental research on tungsten alloy spherical fragments penetrating into carbon fiber target plate

A ballistic projectile launching device was used to study the penetration behaviors of tungsten alloy spherical fragments of various diameters into carbon fiber composite target plates of different thicknesses. Based on the ballistic test results, we obtained the relationship between ultimate penetration velocity, target plate thickness, and fragment diameter as well as the relationship between the fragment penetration energy and fragment incident velocity. Using dimensional analysis, we obtained a formula relating the incident fragment velocity and the fragment penetration energy, which showed good agreement with the experimental values. We also analyzed the main fracture mode and the energy absorption mechanism of the carbon composite target plate under high-velocity impacts of tungsten alloy spheres and investigated the experimental damage modes of the target plate at different fragment velocities during the ballistic impact.

Computational analysis of aluminium alloy plates against conical-nose steel projectile

The usage of aluminium alloy in shielding structures is becoming prevalent choice due to its low density. Even then, articles and reports describing the experimental and computational analysis of such problems are still limited. This paper illustrated the computational analysis of AA5058 against impact of hardened steel projectiles with conical nose. The computational analysis was performed using finite element code-ANSYS. The target plate used was in shape of circular disc of 500 mm diameter and fixed at its curved face. However, wide range of thickness of target plate i.e., 15 mm, 20 mm, 25 mm and 30 mm were considered in the work reported. The projectile considered was of 20 mm diameter and 98 mm long. The conical shape was provided on projectile for 30 mm length on one of its sides. The target material was modeled in finite element code using Johnson-Cook constitutive model. The limiting ballistic velocity of target material was computationally investigated considering initial and residual velocities of projectile. The ballistic limiting velocity for target plate with 15 mm, 20 mm, 25 mm and 30 mm were reported as 214 m/s, 245 m/s, 250 m/s and 300 m/s respectively. Also, the residual velocity for the complete perforation in case of all the variation of thicknesses of target plate was observed and reported. The results obtained from computational analysis were found in good agreement with the analytical model presented elsewhere.

Numerical simulation analysis of PELE penetrating target plates with different thicknesses

PELE (Penetrator with Enhanced Later Effect) is a new type of ammunition, which does not need to be filled with explosives and fuses, but has the function of armor piercing projectile and grenade at the same time. The numerical simulation of a 60 mm diameter PELE penetrating target was investigated. The results show that in the process of the target plate becoming thicker, the transverse effect first increases and then weakens, and the optimal target plate thickness range is 4-6 cm; the properties of the core material have an important influence on the transverse effect of PELE; with the increase of the core radius, the radial velocity of the fragments after PELE penetrating the target first increases, then decreases and then increases, and the optimal core radius is 2-2.6 cm.

WITHDRAWN: Numeric projectile impact simulation on a server utilizing LS-DYNA

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Simulation of Fragmentation Characteristics of Projectile Jacket Made of Tungsten Alloy after Penetrating Metal Target Plate using SPH Method

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.

Ultrasonic Detection of Spall Damage Distribution Subjected to Plate Impact Test with Different Thickness

Plate impact test on medium carbon steel were carried out to the target plate by impacting the flyer plate with one-third and two-thirds thickness of the target plate. The spall damage within the target plate was evaluated non-destructively with a low frequency scanning acoustic microscope as well as ultrasonic velocity and backscattering intensity. We observed the spall damage distribution by the B-and Cscan images. The distribution of spall damage through the plate thickness depends on the tensile stress area within the target plate. The difference of spall damage distribution was investigated by the plate impact test by flyer plate with different thickness. In the plate impact test by the flyer plate with 1/3 target plate thickness, the spall damage was generated by tensile stress area which superposed in the back surface side. On the other hand, in the case of 2/3 target plate thickness, the spall damage was detected at the impact surface side. By generating the spall damage in the different position through the target thickness, it will be possible to evaluate the accumulation of spall damage by reflection and transmission of the stress wave at the internal damage subjected to repeated impact.

Ballistic performance of armour grade heat treated steel using explicit dynamics

Impact, damage and penetration modeling of thick-section are of great importance to many industrial, automotive, aerospace and defense applications. Now a day’s simulation has gained wide attention because of its versatility to predict the results with a nearer approximation to obtained experimental values. This investigation deals with combination of composite type of brass based lead core projectile and heat treated tempered armor grade steel to evaluate the ballistic performance using 3D-nonlinear dynamic explicit finite element code AUTODYN. The simulated and experimental results are found to be in the close proximity. Armor grade steels are widely used materials in defense applications especially as outfit of combat vehicle because of their high strength, high hardness, toughness and economical. These steels are extensively used because of their capability to defeat kinetic energy of projectile on its initial impact and successively absorb the residual energy. It has been understood from various literature that the profile of penetrated projectile is composite in nature instead of homogenous one. Thus, the present investigation deals with modeling of both projectile and target using CATIA and modeled entities are imported into the ANSYS workbench. Similar boundary conditions and material properties were assigned based on available in literature to the thickness of target plate which is used in fabrication of armour vehicles. The results obtained are compared with experimental findings as available in open literature and it can be taken to be in the acceptable limits. Hence the developed model can be considered as one of the tools for accessing the ballistic performance to validate the thickness of armour grade steel.

Effect of Reynolds Number, Hole Patterns, and Target Plate Thickness on the Cooling Performance of an Impinging Jet Array—Part II: Conjugate Heat Transfer Results and Optimization

This study comprehensively illustrates the effect of Reynolds number, hole spacing, nozzle-to-target distance, and target plate thickness on the conjugate heat transfer (CHT) performance of an impinging jet array. Test models are composed of a specific thermal-conductivity material which exerts a matched model Biot number to that of engine condition. High-resolution temperature measurements are conducted on the impinging-target plate utilizing steady liquid crystal (SLC) with Reynolds numbers ranging from 5000 to 27,500. Different streamwise and spanwise jet-to-jet spacing (i.e., X/D and Y/D: 4–8), nozzle-to-target plate distance (Z/D: 0.75–3), and target plate thickness (t/D: 0.75–2.75) are employed to compose a total of 108 different geometries. Experimental measured temperature is utilized as boundary conditions to conduct finite element simulation. Local and averaged nondimensional temperature and averaged temperature uniformity of target plate “hot side” are obtained. Optimum hole spacing arrangements, impingement distance, and target plate thickness are pointed out to minimize hot side temperature, amount of cooling air and to maximize temperature uniformity. Also included are 2D predictions with different convective boundary conditions, i.e., local 2D distribution and row-averaged heat transfer coefficients (HTCs), to estimate the accuracy of temperature prediction in comparison with the conjugate results.

The Numerical Simulation of behind Armor Debris by Shaped Charge Jet Penetration

In order to study the aftereffect of the target plate penetrated by shaped charge jet , with the help of nonlinear dynamics solver AUTODYN, the SPH algorithm was adopted to simulate the whole process of jet penetrating the armor plate with different thickness under the condition of vertical. Results show that while the jet head perforating the plate, the behind armor debris (DAB) cloud will be formed, and the axis of symmetry of the "ellipsoid" is the jet direction. However, with the increase of target plate thickness, the behind armor debris number reduced, largest fragment emission angle also reduced.

Semi-theoretical analyses of the concrete plate perforated by a rigid projectile

Based on the three-stage perforation model, a semi-theoretical analysis is conducted for the ballistic performances of a rigid kinetic projectile impacting on concrete plates. By introducing the projectile resistance coefficients, dimensionless formulae are proposed for depth of penetration (DOP), perforation limit thickness, ballistic limit velocity, residual velocity and perforation ratio, with the projectile nosed geometries and projectile-target interfacial friction taken into account. Based on the proposed formula for DOP and lots of penetration tests data of normal and high strength concrete targets, a new expression is obtained for target strength parameter. By comparisons between the results of the proposed formulae and existing empirical formulae and large amount of projectile penetration or perforation tests data for monolithic and segmented concrete targets, the validations of the proposed formulae are verified. It is found that the projectile-target interfacial friction can be neglected in the predictions of characteristic ballistic parameters. The dimensionless DOP for low-to-mid speed impacts of non-flat nosed projectiles increases almost linearly with the impact factor by a coefficient of 2/(πS). The anti-perforation ability of the multilayered concrete plates is dependent on both the target plate thickness and the projectile impact velocity. The variation range of the perforation ratio is 1–3.5 for concrete targets.

Time resolved friction during dry sliding of metal on metal

In the present study, plate impact pressure–shear friction experiments are conducted to provide insight into time-resolved dry sliding characteristics of metal on metal at normal pressures of approximately 1.5 GPa, slip speeds up to 60 m/s and interfacial temperatures as high as 800°C. The plate impact friction experiments represent a significant improvement over conventional dynamic friction experiments by allowing control of interfacial tractions with the use of combined pressure–shear loading waves instead of manipulating actuator motion. Also, by measuring the combined normal and transverse motion of the rear surface of the target plate, critical frictional parameters such as the applied normal pressure, the interfacial slip resistance, and the interfacial slip speeds can be interpreted by using the framework of one-dimensional plane wave analysis. The experiments are conducted on a Carpentor Hampden tool-steel (D3)/Ti–6Al–4V tribo-pair. The frictional state at the tribo-pair interface is varied by varying the impact velocity and/or the surface roughness of the impacting surfaces. Moreover, by appropriate selection of flyer and target plate thickness the tribo-pair interface is subjected to step changes in normal pressure and step changes in applied shear stress. The results of these experiments provide new insights into the evolution of interfacial sliding resistance with accumulated interfacial slip, and its dependence on surface roughness, slip velocity, normal pressure and interfacial temperature.