Ballistic trauma caused by military rifles: experimental study based on synthetic skull proxies

Rifles are often involved in violent deaths such as homicide and suicide. Consequently, expert knowledge and experimental forensic investigations are important to clarify the nature of ballistic trauma when applied to the human head and neurocranium. This study investigated differences in entrance wound morphology with Synbone® spheres which are described as being comparable to human flat bones. A series of ballistic experiments were conducted using two different rifle calibers (5.56 × 45 mm and 7.62 × 39 mm Full Metal Jacket (FMJ)). Synbone® spheres were used for close-range 0.3 m simulated executions as well as at 25 m and 35 m to simulate urban and military engagements. Results were compared with previously published experimental studies using similar military ammunition. In our study, entry wound morphology closely resembles real forensic cases compared to exit wound and overall shape morphology independently of the distance and the caliber. Circumferential delamination was clearly visible with full metal jacket (FMJ) rounds, yielding similar damage pattern morphology to the human crania. This study documented the presence of hydraulic burst or shock in all ten rounds from all three distances. Krönlein shots were also observed in some cases. Synbone® spheres constitute an acceptable synthetic surrogate for ballistic experiments. The present study offers new initial data on the behavior of Synbone® proxies in ballistic testing of military ammunitions; FMJ gunshot injuries to the human head, for distances that have not previously been published, suggesting that efficient tests can take place under these conditions. Further research on experimental ballistics with a larger number of controlled factors and multiple repetitions is recommended to verify the results of this pilot study before applied in forensic simulations.

Effect of Corundum and Basalt Aggregates on the Ballistic Resistance of UHP-SFRC

Ultra-high-performance steel-fibre-reinforced concrete (UHP-SFRC) is a technologically advanced composite with a high ability to absorb and dissipate mechanical energy. This work investigates the possibility of increasing ballistic resistance by adding different percentages of corundum and basalt aggregate into this type of concrete. The most common type of ammunition, a 7.62 mm × 39 mm calibre with a full-metal jacket and a mild-steel core (FMJ-MSC), was used to test all samples. The size of the damage and the mode of failure were determined using a 3D scanner operating on the principle of photogrammetry. The experimental campaign showed that the addition of basalt and, especially, corundum aggregate has a positive effect on ballistic resistance. In particular, the increase in compressive strength and the slight decrease in depth of penetration (DOP) was observed in the case of the usage of the corundum aggregate.

A Simplified ALE model for finite element simulation of ballistic impacts with bullet splash – development and experimental validation

An original simplified finite element model is proposed to simulate the effects of non-penetrating ballistic impacts causing the so-called bullet splash phenomenon (complete bullet fragmentation), while no fragmentation is caused to the target. The model is based on the Arbitrary Lagrangian Eulerian formulation (ALE) and it simulates the impact as a fluid-structure interaction. The bullet splash phenomenon has been tested by experimental analyses of AISI 304L plates impacted by 9x21 FMJ (full metal jacket) bullets. The model has been developed with the aim of creating a simplified approach to be used in the industry and forensic sciences to simulate the non-penetrating interaction of soft impactors with hard targets. Comparisons between evidence and simulation results lead to the conclusion that the proposed approach can be used in a conservative way to estimate both local and global effects of bullet-splash phenomena.

Karakteristik Fiber Metal Laminate Akibat Beban Impak Balistik Dari Peluru Kaliber 9 mm Full Metal Jacket (FMJ)

<p class="Abstract"><span lang="EN-GB">Estimated damage levels from ballistics impact zone provide valuable information to make bulletproof materials more effective. Therefore, this study aims to determine the impact of ballistics including hole shape, hole depth, macro, and microstructure on fiber metal laminate. The characteristics of ballistics impact for each configuration target is obtained from experiment and comparison based on simulations with finite element method. Test experiments used short-barreled fire guns at a distance of 5 meters with a normal attack angle based on the National Institute of Justice standard. Simulation with Johnson-Cook plasticity models for aluminum plate and orthotropic material model for kevlar/epoxy. The experiment and simulation results showed that the projectile is able to perforate the first layer (aluminum plate) and the second layer (Kevlar/epoxy) while the last layer (backplate) is deformed to form a bulge. The aluminum plate is perforated by the failure of petaling formation on the backside and spread of dimple fracture around the area of the petal which indicates ductile fracture while kevlar/epoxy is perforated by projectile with failure of fiber fracture on primary yarn, fiber pull-out, fiber stretching and fiber rupture.</span></p>

Early and Midterm Results of Stent Endarterectomy for Left Anterior Descending Coronary Artery “Full Metal Jacket”

Objective: Modern coronary interventional practice can result in coronary vessels that are totally stented. The term “full metal jacket” has been coined to refer to vessels that have an overlapping stent in series along the whole length of the vessel. This poses a serious challenge to surgical revascularization, particularly when a left internal thoracic artery (LITA) to the left anterior descending (LAD) needs to be undertaken. We evaluated the early and midterm results of on-pump coronary artery bypass grafting (CABG) following “stent endarterectomy” for the LAD with LITA to LAD grafting. Methods: During October 2017 to September 2020, 21 patients presented with multi-vessel disease and a totally occluded LAD with a stent full metal jacket. No distal target for LITA grafting was available, despite a viable myocardial territory. The LAD was endarterectomised, removing the column of totally occluded stents with the medial wall of the vessel, leaving the proximal stent in place to avoid competitive flow. Long length anastomosis was then undertaken with the LITA graft. Postoperatively, patients were followed up clinically and by coronary computed tomography (CT) angiography at 6- and 18-month intervals. All patients were discharged on a combination of aspirin and warfarin for three months and then aspirin and clopidogrel for the rest of the first year and then aspirin alone for life. Results: Patients had a mean age of 58.07 ± 2.06 yr. Sixteen (76.2%) were males, 13 (61.9%) patients were diabetics, 18 (85.7%) were hypertensive, 15 (71.4%) were dyslipidemic, six (28.6%) were obese, 11 (52.4%) were smokers, and five (23.8%) had positive family history of ischemic heart disease (IHD). The number of grafts per patient ranged 3-5, with a mean cross-clamp time of 64.71± 8.84 min. There were no postoperative deaths nor MI clinically, by electrocardiogram (ECG) criteria nor by troponin or CK-MB. In-hospital complications included one (4.8%) patient who required re-exploration for bleeding, one (4.8%) developed a superficial wound, and three (14.3%) developed atrial fibrillation (AF), during their hospital stay. Mean hospital stay was 7.71±1.73 days. All patients completed the 6-month follow up showing patent LITA to LAD with coronary CT angiography. One patient was lost to follow up after six months; five patients are awaiting their 18-month CT angiography, while 15 (71.4%) patients have completed their 18-month CT angiography, and all have a patent LITA to LAD. Conclusions: Stent endarterectomy for a totally occluded LAD with a full metal jacket and viable myocardial territory is a safe procedure with good early and midterm results. This technique should be considered in these difficult cases presenting for revascularisation when no other option is available.

Ballistic Impact Resistance of Bulletproof Vest Inserts Containing Printed Titanium Structures

Finite element modeling of ballistic impact of inserts containing titanium structures were presented in the article. The inserts containing an additional layer made using additive manufacturing technology were analyzed. The layer was created from repetitive elements made without connections (adjacent cells were inseparable). Four variants of printed titanium structures were placed between layers of Twaron CT 750 aramid fabric to create ballistic inserts. In order to assess the ballistic resistance of the inserts, numerical simulations of ballistic impact phenomenon were carried out using LS-Dyna software. In the simulations the inserts were placed on a steel box filled with ballistic clay and were fired at with the 9 × 19 mm full metal jacket (FMJ) Parabellum projectile. The main aim of the work was to check the effectiveness of such solutions in soft ballistic protection applications and to select the most effective variant of 3D printed structure. Results of the numerical analysis showed a high potential for 3D printed structures made of titanium alloys to be used for bulletproof vest inserts. In all analyzed cases the projectile was stopped by the armor. In addition, thanks to the cooperation of adjacent cells, the projectile energy density was distributed over a large area, as evidenced by large volumes of hollows in the ballistic clay. The indentations in the ballistic clay obtained in the simulations were significantly lower than the acceptable value for the back face deformation (BFD) parameter required by international body armor standards.