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BACKGROUND: Concrete structures utilized in protective buildings such as ammunition depots and bunkers are susceptible to missile impacts, necessitating a comprehensive ballistic assessment involving penetration and perforation mechanics. Most of the empirical and analytical models for projectile penetration in concrete primarily focus on determining the penetration depth, scabbing, and perforation thicknesses. Concrete structures subjected to firearm attacks exhibit distinct fracture modes that can aid in identifying the firearm used and potential firing locations. AIM: This study aims to comprehend the effects of the angular firing of a 9 mm full metal jacketed projectile on aerated concrete blocks, fired from a 5 m range. The goal is to generate hypotheses and conclusions based solely on the observable damage resulting from bullet impacts. A meticulous analysis of the incurred damages can unveil a range of possibilities. MATERIALS AND METHODS: The sample comprised 12 aerated concrete blocks, each subject to 919 mm bullets fired from four different angles: 0, 15, 30, and 45. The relationship between impact angle and entry hole dimensions was established using the best-fit ellipse method. RESULTS: Examination of the fracture pattern revealed significant damage at both entry and exit holes for a 0 impact angle. As the impact angle increased, the exit hole diameter progressively decreased, culminating in no perforation at a 45 angle. This trend correlated with fracture patterns near entry and exit holes, along with energy dissipation at the impact site corresponding to the impact angle. CONCLUSION: A trend was observed between projectile energy loss upon impact and resultant damage to aerated concrete block surfaces. Analysis of aerated concrete block components deposited on the bullets, including rifling details, can help link them to the gunshot openings and firearms recovered at crime scenes.

BACKGROUND: Injuries from atypical firearms are highly variable in their morphology and often differ from typical gunshot injuries. This can lead to problems in forensic diagnostics. Knowledge of the atypical weapons design and discovery of atypical projectiles inside a body or at crime scene allows proper injury nature assessment. CASE PRESENTATION: The morphological features of the entrance and exit gunshot wounds of the occipital and frontal bones caused by an atypical projectile ― a concrete nail 4.560 mm are described. The entrance gunshot injury had typical morphological features associated with the specific action of the projectile (a tissue defect, internal beveling of wound). The exit wound was atypical due to the incomplete exit of the concrete nail from the cranial cavity, as well as the anatomical features of the damaged area. CONCLUSION: Atypical firearms and projectiles are diverse and their samples may have many unique designs and technological features knowledge of which may be crucial for forensic examination of gunshot injuries. A comprehensive medico-legal assessment of the injury gunshot nature and the number of shots is traditionally based on the injury morphology and revealing the gunshot residues. However, the presence of projectiles and/or their fragments in the body facilitates the solving of expert tasks. In our case the key to the correct interpretation of the wounds nature was the presence in the skull of an atypical projectile ― a concrete-nail.

BACKGROUND: According to the literature, the speed and kinetic energy of the bullet within 100 m of flight varies slightly, on the basis of which we put forward a scientific hypothesis that there were no significant changes in the picture of gunshot injuries formed when firing a hunting rifle and subsequent ricochet, when changing the values of pre-grade distance. AIMS: Determining the effect of the pre-barrier distance on the characteristic of gunshot injuries resulting from a bullet ricochet when fired from a smooth-bore weapon. MATERIAL AND METHODS: A ballistic experiment was conducted to model the ricochet of a bullet and the formation of gunshot damage to stray targets when fired from a 12-caliber IZh-27 M hunting rifle using 12/70 Gold hunting bullet cartridges with a 32 gr Gualandi bullet, at a barrier of steel brand St45, at a meeting angle of 30 degrees, from the pre-barrier distance values 12346810 m. The formed damage was subjected to visual examination, measurement, microscopic, photographic, research in ultraviolet and infrared rays, contact-diffusion, mathematical-statistical methods. RESULTS: The study demonstrated that the change in the pre-barrier distance values within these limits does not lead to the formation of statistically significant differences in the main parameters characterizing gunshot injuries: shape, presence of a tissue defect, dimensions of injuries, coincidence of the orientation of the longitudinal axis of the damage with the longitudinal axis of the barrier, the presence and dimensions of additional damage, the dimensions of wiping areas in the area of additional damage, the sizes of products of the shot deposition areas on the target surface (p 0,050). CONCLUSION: Established patterns can be used in conducting ballistic experiments to model a bullet ricochet, as well as for reconstructing the circumstances of the incident during a situational examination in cases of gunshot injuries formed as a result of a ricochet when firing from a smooth-bore weapon.

BACKGROUND: The understanding of the dynamics of the trajectory is important in ballistics to estimate the values of various flight variables accurately. The paper deals with the study of the fundamental principles of external ballistics, which allows to delve into the trajectory characteristics of the free flight trajectory of seven. 308 caliber bullets by numerically solving the point-mass equations of motion. Numerical solutions were performed by writing scripts in the Python programming language and using the Matplotlib library to plot simulated trajectories. AIM: the three aims of the study were to observe the variation of CD with Mach number (Ma) of flight and calculate an average CD for each bullet under consideration. Further, solving the 3-DoF (Degrees-of-Freedom) Point-Mass trajectory equations of motion for the given bullets (along side observing the effects of range winds on the trajectory behaviour as a variable). And finally, solving the flat-fire approximation with analysis of the effects of a crosswind. MATERIALS AND METHODS: Simulations of free-flight trajectories of seven different 7.62 mm/.308 rifle bullets (designated B0B6) have been carried out by the numerical solution of the equations of motion. The average drag force coefficients (CD) for B0B6 have been calculated by scaling the variation of CD with the Mach number of flight with reference to the G7 standard projectile. The Point-Mass trajectory model and its Flat-Fire approximation have been studied with and without the effect of range winds. The solutions of the systems of equations have been carried out by writing scripts in the Python programming language. RESULTS: It is observed that an increase in the bullet weight and consequently the sectional density lowers the CD. As expected, it is seen that the bullet with the highest drag (B0) has the shortest range and lowest apogee, while lower drag bullets fly further and higher. The crossover of trajectories is observed at ~30 angle of gun elevation, which implies that the maximum range is not achieved when fired at 45, as is the case with vacuum trajectories. Flat-fire approximation of the point-mass model was also solved to observe trajectories and crosswind deflections of the bullets when fired at 5 angles of elevation. CONCLUSION: This project presents the numerical solution of equations of motion of the Point-Mass model for a bullet fired from a gun to computationally simulate its trajectory. A group of seven 7.62 mm/.308 rifle bullets were chosen as samples to simulate free-flight trajectories. The programming language Python is well-equipped to carry out numerical solutions of systems of differential equations owing to its library of in-built functions which assists in writing an efficient script and reduces computational load. This method of solution can be applied with suitable modifications in the field of forensic ballistics for the reconstruction of bullet trajectories and to form a conclusion based on the available evidence from a crime scene.

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Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal on Communication / Tongxin Xuebao is the property of Journal on Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The high-speed ice-ball impact damage research of epoxy resin/carbon fiber 3D four-way braided composites was carried out. Using the air gun impact test system, ice balls with three different impact velocities were used to conduct impact tests. After the test, industrial CT scans were performed on the main damage positions of the test pieces, and the internal damage forms were observed. The composite macro constitutive model based on surface unit-cell and interior unit-cell and a strain rate related material model of the ice were used to establish the finite element model. The simulation model was compared with the test. The results show that the damage of the matrix in the surface unit-cell area is more serious than that in the interior unit-cell area, the damage area of the front surface is generally larger than that of the back surface, the oblique impact angle has an influence on the damage area and damage location. As the impact angle decreases, the damage area of the composite material also decreases. Increasing the thickness of plate can improve the ability to absorb energy and reduce the damage area of the material. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Mechanical Strength / Jixie Qiangdu is the property of Zhengzhou Research Institute of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Aero Weaponry is the property of Aero Weaponry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)