Bullet Impact Research Articles

Rapid analysis method of helicopter fuselage bullet damage based on bullet penetration theory

Helicopter fuselage has a complex shape and structure. Numerical simulation analysis of helicopter fuselage bullet damage based on the finite element method is computationally intensive and takes a long time. It is difficult to quickly analyze and evaluate helicopter fuselage bullet damage in a complex multi-bomb environment. To this end, the bullet penetration theory and the bullet impact calculation model were coupled to establish a rapid analysis method for helicopter fuselage bullet damage, and the accuracy of the rapid analysis method was verified by comparing with test results and finite element numerical simulation results. Then the helicopter fuselage bomb coordinates, residual speed and fuselage damage area of the multi-bomb strike were studied. Research shows that the residual velocity calculated by the rapid analysis method is consistent with the test results; compared with the finite element numerical simulation of bullet damage, the maximum error of the projectile residual velocity calculated by the rapid analysis method is 4.7%, and the maximum error of the fuselage damage area is 9.56%, and the calculation time is reduced 92.1%. Computational efficiency is significantly improved. As the incident angle of the projectile increases, the residual velocity decreases and the damage area increases; when the incident angle of the projectile is too large, the projectile cannot penetrate the surface of the fuselage, causing sink-like sliding damage, causing a larger area of damage.

Hybrid Soft Ballistic Panel Packages with Integrated Graphene-Modified Para-Aramid Fabric Layers in Combinations with the Different Ballistic Kevlar Textiles.

The purpose of the research discussed in this article is to explore the possibility of creating hybrid soft ballistic panel (BP) package variants by integrating into their composition layers of graphene-modified para-aramid fabrics in combinations with the different ballistic Kevlar textiles to improve the durability of the first layers of the soft ballistic panel. To address this goal, the liquid-phase exfoliation (LPE) method was used for integrating dispersions into composites to solve a number of topical problems in the stages of the technological sequence development of processing methods and optimizing processing parameters in accordance with the processing specifics of aramid textiles to achieve the desired properties of modified ballistic fabric, including the provision of coating adhesion to the surface to be modified. To test the results, ballistic experiments were performed and the back-face signature (BFS) of bullet impact on a backing material was analysed according to standards. Bullet impacts on the first ballistic protective fabric layers were also studied.

Analysis of Bullet Impact Locations in the 10 m Air Pistol Men’s Competition Based on Covariance

The purpose of this study was to quantify the bullet impact locations of the men’s 10 m air pistol competition and propose objective metrics for evaluating shooting techniques. We automatically collected data from the top 20 competitors’ shooting results using computer vision techniques. Metrics such as x-variance, y-variance, covariance, x-mean, y-mean, root mean square error (RMSE), x-mean score, and y-mean score were computed to investigate correlations among rankings, left–right and up–down shot groups, aiming relationships, and precision. Covariance analysis revealed significant interactions between horizontal and vertical aiming, highlighting the importance of balanced coordination between these directions for high performance. Athletes with lower covariance values, indicating less variation between horizontal and vertical aiming, tended to achieve higher rankings. Additionally, top-ranked athletes exhibited lower RMSE values, underscoring the importance of precision in achieving high scores. In conclusion, this study analyzed the correlation between x and y through covariance, examined its relationship with competition rankings, and proposed new indicators for training and performance enhancement. This study is novel in that it provides quantitative data to correct poor aiming and shooting habits by performing a covariance-based bidirectional correlation analysis, rather than simply analyzing bullet impact locations in a single horizontal or vertical direction. Our approach establishes a foundation for more data-driven and objective evaluations in the sport of shooting.

High-impact dynamic loading method for calibration of triaxial acceleration sensors

Abstract In this study, a high-impact dynamic loading device was designed to generate a three-dimensional pulse excitation signal with high intensity shock acceleration and achieve triaxial synchronous calibration of a triaxial acceleration sensor. A light-gas gun interior ballistic model and a sensor mechanical response model were developed, and the relationships between the bullet impact velocity, barrel length, and initial chamber pressure were obtained. Additionally, the transformation relationship of the sensor’s triaxial acceleration in different coordinate systems was derived. Based on the stress wave theory and the finite element method, the influence of the bullet impact velocity on the variation pulse, and different slope and deflection angles on the triaxial acceleration were analyzed. By optimizing the parameter design, machining the prototype, and conducting high-impact dynamic loading tests, the results showed that the deviation between theoretical and measured values of the generated triaxial acceleration signal was small, and the maximum deviation was less than 4%. This indicated that the proposed high-impact dynamic loading device satisfied the calibration requirements for calibrating triaxial acceleration sensors, which can generate a three-dimensional acceleration with a peak value of not less than 700 000 m s−2.

Quantitative Characterization of the Perforation Behaviour of Direct Recycled Aluminum Alloy 6061 Plates Subjected to High-Velocity Impact

This study aims to establish the perforation behaviour of direct recycled AA6061 to help establish the properties of the current most optimized direct recycled AA6061 through the hot press forging technique. This was achieved by subjecting direct recycled AA6061 plates of varying thickness to high-velocity impacts using a single-stage gas gun setup. The impactor is a hemispherical steel projectile of 13mm in length and 8.5mm in diameter. Plates of 3,4,5 and 10mm thickness were tested at velocities ranging from 120 m/s to 402 m/s. The deformation profiles of the impacted plates were captured and analyzed to quantitatively establish the perforation behaviour of recycled AA6061 plates. The plates showed irregular and non-axis symmetric patterns of deformation hinting the material exhibits anisotropic properties. The changes in the deformation profile were investigated in relation to changes in impact velocities and plate thickness were made to understand how they impact the profile. The deformation area was observed to be decreasing when the bullet impact velocity was increased. Higher velocity impact events lead to more material ejection from the plate in the form of fragmentation. Additionally, the deformation zone was observed to be getting smaller with an increase in the thickness of the plate. Thicker plates were found to have more fragmentation compared to thinner plates. Ductile failure characteristics such as petal formation and plugging were observed along with brittle characteristics such as fragmentation and conal fractures. Lower-velocity impacts lead to more energy absorbed by the target plates. Thicker plates observed more of the bullet’s energy. Through experimentation, the deformation behaviour of the directly recycled AA6061 material was established. This data can be used as a base for further research into the material’s behaviour characterisation.

Ballistic behavior of bioinspired layered-and-staggered concrete

Inspired by the structure of abalone shells, a layered-and-staggered concrete system composed of concrete tiles joined with rubber mortar was proposed for ballistic protection. Ballistic tests demonstrated that, when subjected to Type 53 API bullet impact at velocities ranging from 780 to 815 m/s, the layered-and-staggered concrete outperformed both steel fiber reinforced bulk concrete and simple layered concrete with comparable compressive strengths in terms of reducing bullet penetration depth. Furthermore, damage in the layered-and-staggered concrete was primarily confined to areas surrounding directly impacted tiles or joints; cracks on the impact face did not propagate radially as observed in bulk concrete but instead deflected along weak interfaces between adjacent tiles. Additionally, crack deflection and bullet yawing were observed in the thickness direction of the layered-and-staggered concrete targets, aligning with expectations for bionic design effects. Incorporating steel micro-fibers into the layered-and-staggered system enhanced individual tile's impact resistance but did not reduce bullet penetration depth. The proposed layered-and-staggered concrete exhibits promising potential for practical applications, particularly in scenarios requiring prompt repair of damaged components.

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

Validation of the lead-in method in a practical shooting scenario.

The ability to determine bullet trajectories after a shooting incident can allow investigators to reconstruct the locations of individuals and the sequence of events that took place. By using trajectory rods, investigators can be provided with an immediate visual estimate as to what the path of the projectile may have been. In certain instances, the use of the probing method with trajectory rods is not appropriate due to their being a single, thin target material, or no secondary bullet impact site. In these cases, other methods such as the lead-in or the ellipse method may be useful. Overall, the lead-in method has not been well studied in the application to practical scenarios, such as those including bullet impacts on vehicle metal surfaces. This study has explored the accuracy of the lead-in method when a bullet impacts a typical vehicle metal surface using three firearm calibers, three blind participants, and two non-blind participants. The results of this study have shown that each caliber has its own characteristic error curve. In general, it was found that the lower the impact angle, the less errors were made by the participants. As the impact angle increases, the measurement errors increased, due to the smaller lead-in area present. The errors were found to have a wide range, with some being as low as 1° and some being as high as 13.9°. Further, it was found there was no significant effect on the errors of blind versus non-blind participants.

Study on bullet impact performance of the HATO-based explosives

In order to study the vulnerability of 1,1'-dihydroxy-5,5'-bistetrazole dihydroxylamine salt (HATO) based explosives, a comparative study of the bullet impact vulnerable characteristics of HATO-based explosives and HMX-based explosives were carried out by using the 12.7 mm bullet impact test method of the 700-group of the Military Mixed Explosives Formulation and Performance Test Methods. The results of the study indicate that due to the friction and impact sensitivities of the HATO and the HMX explosives are similar, and the bullet impact response degree and the safety performance of the HATO-based explosives and HMX-based explosives is equivalent too.

Analysis of the Brownian Motion Approach for Ballistic Resistance Evaluation Using the Maximum Likelihood Inference

Armor technologists’ improvement of protection systems led to the design of complex systems. Given the risk factor on human life, increasing requirements on the ballistic resistance evaluation are imposed. Consequently, an increased effort is dedicated to estimating the perforation probability curve as a function of the bullet impact velocity. The main limitation of methods that fits a normal law to perforation velocities is their purely statistical character. A Brownian-based approach that couples the system response variability and physics was proposed using the Chi-square and Kolmogorov-Smirnov criterion function for model parameters estimation. One major limitation of this inference approach is the large experimental database required for its execution. The contribution of this paper is the introduction of the maximum likelihood inference for parameters estimation of the Brownian-based approach. The agreement between the obtained results and the experimental ones confirms the appropriateness of the likelihood inference to solve the studied problem. Moreover, the estimations uncertainty was analyzed and compared to the existing method ones. It was observed that the proposed model reduces the confidence intervals on key velocity estimations. Accordingly, the present work encourages the adoption of this proposed methodology in a laboratory context with a restrained sample size.

Skin simulants for wound ballistic investigation – an experimental study

Gunshot wound analysis is an important part of medicolegal practice, in both autopsies and examinations of living persons. Well-established and studied simulants exist that exhibit both physical and biomechanical properties of soft-tissues and bones. Current research literature on ballistic wounds focuses on the biomechanical properties of skin simulants. In our extensive experimental study, we tested numerous synthetic and natural materials, regarding their macromorphological bullet impact characteristics, and compared these data with those from real bullet injuries gathered from medicolegal practice. Over thirty varieties of potential skin simulants were shot perpendicularly, and at 45°, at a distance of 10 m and 0.3 m, using full metal jacket (FMJ) projectiles (9 × 19 mm Luger). Simulants included ballistic gelatine at various concentrations, dental silicones with several degrees of hardness, alginates, latex, chamois leather, suture trainers for medical training purposes and various material compound models. In addition to complying to the general requirements for a synthetic simulant, results obtained from dental silicones shore hardness 70 (backed with 20 % by mass gelatine), were especially highly comparable to gunshot entry wounds in skin from real cases. Based on these results, particularly focusing on the macroscopically detectable criteria, we can strongly recommend dental silicone shore hardness 70 as a skin simulant for wound ballistics examinations.

An algorithm to determine the impact point on the target surface using ultrasonic sensors

The article addresses the issue of using ultrasonic sensors to determine the bullet's impact point on the target surface, serving to evaluate the results of firing tests. The method of determining the impact point is based on the time difference of the time of arrival of the sound wave to the ultrasonic sensors. The constructed equations are complex nonlinear equations. To be able to solve this system of equations, the construction of the equation is combined with the arrangement of sensors to isolate each unknown, helping to simplify the solution of the system of equations. Sensor layout diagram and impact point determination algorithm have been proposed.

Assessment of Bullet Impact and Failure Mechanism of Concrete Containing Polythene Aggregates

The time from the initial stage of existence on Earth, the war continued. In this concern, India’s DRDO (Defence Research and Development Organization) and OFB (Ordnance Factory Board) worked appreciatively to develop new protective gear against assault weapons. The main focus of bullet or blast proof structures is to safeguard the life of soldiers, their accessories and gears, along with confidential and classified acquittance, firearm and ammunition, and sensitive systems. Defence structures like bunkers and tranches were designed in such discipline to keep them active round-the-clock with heavy armoury and made functional near to Line of Control (LOC) and Line of Actual Control (LAC) which oppose the effect of highly intensive blast waves. In such a manner, field testing with different Indian assault rifles i.e. INSAS (Indian Small Arms System), SIG 716i (US origin), and INSAS LMG (Indian Small Arms System-Light Machine Gun) was made from different ranges starting from 50mts to 300 mts extreme. Such structures were designed to protect the safety of soldiers from the bump of bullet effect. Structures designed are very strong and durable with opposition to high lateral load and visible surfacing. Construction material used for building plays a foremost role. The investigation is based on unique and advanced ideas in designing the defence structures. The investigation elaborates on the difference between conventional designing and the special designing of defence structures, as the advanced concept of polythene aggregates performs better than ordinary concrete.

REMOVED: SAMAS 2: Structural health and ballistic impact monitoring and prognosis on a military helicopter

The development of a Structural Health Monitoring and Prognosis (SHMP) tool for corrosion degradation and bullet impact damages is matter of SAMAS 2, a project coordinated by the European Defense Agency (EDA) and funded by 2 EDA Member States (Italy and Poland). The aim of SAMAS 2 is to increase the machine availability by directly monitoring the corrosion degradation as well as detecting the ballistic impact occurrence and - in case of crack nucleation - monitoring its propagation inside the structure, concept at the basis of Structural Health Monitoring (SHM) systems. In this way it would be possible to get a real time knowledge about the damage situation, thus setting a Condition Based Maintenance (CBM). The current paper is a summary of the advances in the project, covering all the involved engineering areas, from the adopted sensor network to the FEM simulation based on Reduced Order Modelling techniques and coupling with Machine Learning algorithms (Digital-Twin model), thus coming to the definition of a robust methodology for SHM design. The possibilities for result exploitation, as well as the points requiring further advances, are going to be presented.

Estimation of Impact Strength of Kevlar/Basalt and Kevlar/Glass Interwoven Composite Laminate after High-Velocity Bullet Impact

The application of composite materials has increased so drastically in the aerospace industry. The Impact strength signifies the importance of composite materials when exposed to suddenly applied loads. This paper is focused on describing the behavior of interwoven kevlar/glass-epoxy and kevlar/basalt-epoxy composite laminate under high-velocity bullet impact. The composite lamina of kevlar/glass and that of kevlar/basalt are prepared using three different weaving techniques. The composite laminates are prepared using the compression moulding technique. The laminates have been subjected to high-velocity bullet impact. The velocity range is from 220 m/s to 260 m/s. The impact damage area in the laminate has been assessed through ultrasonic pulse echo submerged nondestructive technique. The impact strength has been calculated using the damaged area derived using the impact energy absorbed by the laminate. The results have shown that the maximum impact which found out to be kevlar/basalt (KB 1 × 1) is 28.24 J/cm2.

Research on Simulation Model of Unexploded Ordnance Destruction Based on Sniping Method

To evaluate the ability of the sniping method to destroy unexploded ordnance, a simulation model of bullet impact on 38mm stun grenades was established with the SPH-FEM coupling method. The destruction process of unexploded ordnance and residual velocity and direction of the bullet were analyzed at different conditions of impact positions and velocities. The results show that axial or radial top position impact of unexploded ordnance can completely separate primary explosive and main charge, which is more thorough than radial middle and bottom position impact; When shooting at a distance of 50m-250m, unexploded ordnance can be effectively destroyed, with little difference in velocity attenuation. However, after penetrating unexploded ordnance, the flight direction of the bullet will change by 1 ° to 7 °. In conclusion, the simulation model can effectively calculate the process of ordnance destruction and the flight of the bullet; the sniping method prioritizes the use of axial or radial top propellant position impact; The impact bullet has a deviation in flight direction, and it is necessary to take good safety measures in the shooting range to avoid ricocheting out of the field.

Protective performance of shear stiffening gel-modified foam against ballistic impact: Experimental and numerical study

As one of the most widely used personal protective equipment (PPE), body armors play an important role in protecting the human body from the high-velocity impact of bullets or projectiles. The body torso and critical organs of the wear may suffer severe behind-armor blunt trauma (BABT) even though the impactor is stopped by the body armor. A type of novel composite material through incorporating shear stiffening gel (STG) into ethylene-vinyl acetate (EVA) foam is developed and used as buffer layers to reduce BABT. In this paper, the protective performance of body armors composed of fabric bulletproof layers and a buffer layer made of foam material is investigated both experimentally and numerically. The effectiveness of STG-modified EVA in damage relief is verified by ballistic tests. In parallel with the experimental study, numerical simulations are conducted by LS-DYNA® to investigate the dynamic response of each component and capture the key mechanical parameters, which are hardly obtained from field tests. To fully describe the material behavior under the transient impact, the selected constitutive models take the failure and strain rate effect into consideration. A good agreement between the experimental observations and numerical results is achieved to prove the validity of the modelling method. The tests and simulations show that the impact-induced deformation on the human body is significantly reduced by using STG-modified EVA as the buffering material. The improvement of protective performance is attributed to better dynamic properties and more outstanding energy absorption capability of the composite foam.

Optimizing ultra-high performance cementitious functionally graded composite slab towards bullet impact resistance

This study develops functionally graded composite slab (FGCS) by a one-time grouting approach based on the design concepts of ultra-high performance fibre reinforced concrete (UHPFRC) and two-stage concrete (TSC). The anti-penetration performance of the FGCS targets is investigated against 7.62 mm in-service bullets with shooting velocity of 843 m/s. The results show that while the TSC target presents superior bullet penetration resistance, it concurrently poses a significant threat of widespread cracking damage. Upon weighing the factors of bullet penetration and risk of cracking, the FGCS emerges as a more viable candidate for protective structures. The FGCS target is cast through a one-time grouting method, and there is no interface delamination under the projectile impact. The optimized FGCS exhibits enhanced in-service bullet impact resistance and a reduced safety thickness of 80 mm compared to the normal UHPFRC.

Effect of lamination sequence and warhead shape on impact resistance of fiber‐metal laminates

AbstractIn this work, the failure mode and ballistic protection capability of the carbon fiber aluminum alloy laminated target plate under the impact of high‐speed projectile body were studied by ballistic impact test. The effects of the lamination sequence and warhead shape difference on the impact resistance of the laminated aluminum alloy and carbon fiber laminates were analyzed. Two kinds of projectile bodies, flat and oval head, were used to carry out multiple high‐speed impact experiments on four groups of targets with different stacking sequences. By analyzing the result, it is found that the lamination sequence of the target plate has a significant effect on the anti‐impact performance only when the flat head projectile impacts, while the ovoid projectile has almost no effect. In the fiber‐metal composite configuration, the aluminum plate placed in front of the carbon fiber plate showed the best resistance to flat head bullet impact, the ballistic limit speed reached 135 m/s, and the overall impact resistance improved by up to 26% compared with other configurations. Unlike the shear failure caused by flat head projectile, ovoid projectile impact can cause serious tensile and tear damage. Based on the experimental results, it is clear that the laminated structure has better penetration resistance against the flat head projectile, and the placement of aluminum plate on the impact surface can change the failure mode of carbon fiber laminates and improve the energy absorption level of composite plates.Highlights Unlike traditional fiber‐metal laminates, the target plate used in this experiment does not use adhesive, which makes the deformation of the two materials will not affect each other, which is conducive to the study of its own impact resistance. The mechanical behavior and damage failure mode of the target plate under high speed impact load were studied. The impact of ovoid projectile changes the damage failure mode of the target plate. For the configuration of fiber‐metal laminates, the ballistic limit value is as low as 100 m/s, and the energy absorption value fluctuates in the range of 145–190 J with the change of impact velocity. Compared with ovoid projectile, laminated material has stronger impact resistance to flat head projectile. The metal plate arranged on the impact surface can change the damage mode from shear failure to tensile failure, thus greatly improving the ballistic limit and impact resistance, overall impact resistance can be improved by up to 26%.

A New Approach for Protection against Ejection Trajectory of Scabbed Materials of Ultrahigh-Performance Concrete under Projectile Impact

Scabbing on the rear face of concrete under impact produces fragments that act as additional projectiles causing fatality or severe damage to the occupants or systems. Ultrahigh-performance concrete (UHPC) has outstanding properties and has proven efficacy in the impact-resistant design of structures. However, the potential damage due to the impact of fragments of scabbed pieces still prevails. This study developed a new approach for preventing ejection of scabbed materials of UHPC under single and repeated bullet impact (using a single-stage gas gun facility). The ejection of scabbed materials was controlled using woven carbon–epoxy and glass–epoxy laminated composite sheets attached to the rear face of UHPC samples. The ejection of scabbed pieces was controlled in UHPC targets with composite backing in the case of both single and repeated impact under similar conditions. Furthermore, a numerical simulation based on nonlinear finite-element code was performed for repeated impact on a UHPC target with a carbon–epoxy laminated composite. The results of the numerical simulation had a good agreement with the experimental data. Thus, the synergistic effects of steel fiber–reinforced UHPC with composite backing can be used to enhance the impact performance of UHPC.