The experimental and numerical investigation of pistol bullet penetrating soft tissue simulant

Terminal ballistics performance of 9 × 19 mm cartridges in 10% ballistic gelatin: FBI Protocol based analysis of Brazilian-made law enforcement ammunition

PURPOSE

Understanding that a projectile entering the human body can cause damage or destruction to live tissues through a variety of wounding mechanisms - permanent cavity, temporary cavity, and fragmentation - is crucial for researching terminal ballistics and understand the patterns of gunshot wound configuration.

METHODS

The present work tested four different types of ammunition in caliber 9 × 19 mm (Full Metal Jacketed, Gold Hex, Copper Bullet Tactical and Bonded), using ballistic gelatin at 10% as soft tissue surrogate. The tests were based on the Federal Bureau of Investigation Protocol and included shots through bare gelatin, heavy clothing, plywood, steel sheets and auto glass. As a comparison parameter, the American-made Federal™ HST, used by several law enforcement agencies in the USA, was also tested in the same conditions.

RESULTS

The Full Metal Jacketed cartridge had a uniform performance throughout the experiment, showing high penetration levels and no expansion, as expected. Gold Hex demonstrated a strong tendency to fragment with low levels of penetration and weight retention. Copper Bullet Tactical did not achieve the 12" minimum penetration in the soft barrier phases but expanded aggressively. Finally, Bonded only failed to achieve the 12" mark of penetration in phase 5 (auto glass), the hardest barrier in the whole Protocol. Tested for comparison purposes, Federal HST showed aggressive expansion in the initial phases (over 100%), after surpassing the 12" threshold.

CONCLUSION

The study concluded that heavier projectiles (CBC Bonded and Federal HST) performed better than lighter and faster bullets in terms of terminal ballistics.

Low-velocity nail penetration response of muscle tissue and gelatin

Quantitative estimation of soft tissue injuries due to penetration of sharp objects is a challenging task for forensic pathologists. The severity of injury depends on the force required to penetrate the tissue. This study focuses on investigating the amount of force required to penetrate porcine muscle tissue and gelatin simulants (10 % wt) to mimic human muscle tissue when subjected to sharp objects like nail at velocities below 5 m/s. A custom-made experimental setup was used to examine the influence of penetration velocity and nail diameter on penetration forces. Images captured by a high-speed camera were used to track the position and velocity of the nail. A finite element (FE) model was established to simulate the penetration behavior of the tissue and gelatin. The FE simulations of the nail penetration were validated through direct comparison with the experimental results. In tissues as well as in the simulant, penetration forces were seen to increase with increasing nail diameter and velocity. Porcine muscle tissue showed 23.9-46.5 % higher penetration forces than gelatin simulants (10 % wt) depending on nail diameter and velocity; the difference being higher for higher nail diameter and velocity. The ranges of maximum penetration forces measured were 8.6-59.1 N for porcine muscle tissue and 6.8-34.9 N for gelatin simulant. This study helps to quantify injuries caused by sharp nails at low velocities and offers insights with potential applications in injury management strategies and forensic studies.

The experimental and numerical investigation on the ballistic limit of BB-Gun pellet versus skin simulant

The insufficient recognition of injuries by the BB-gun (regarded as toys for children) has led to its increasing misuse without permission, which has caused many public safety issues. Aiming to enhance the understanding of the injuries by the BB-gun, the experimental and numerical study of BB-Gun pellet penetrating "cowhide + gelatine" composite target was comprehensively carried out. It was confirmed from the experiment that BB-Gun is capable of inflicting severe or fatal wounds to important organs, and perforating the skin or not could be employed to evaluate the safety of BB-guns. Moreover, three forms of ballistic limit (including: velocity, kinetic energy and specific kinetic energy) of typical BB were calculated and analyzed by reasonably validated numerical simulation method. Additionally, a formulation was acquired by dimensional analysis based on the simulation results and was verified to accurately predict the ballistic limit velocity of BB with different mechanical properties. The method may help to improve the understanding on the minimal velocity needed to perforate skin and may be advised as the determination of the safety of BB-gun.

Assessment of bullet effectiveness based on a human vulnerability model

Introduction

Penetrating wounds from explosively propelled fragments and bullets are the most common causes of combat injury. There is a requirement to assess the potential effectiveness of bullets penetrating human tissues in order to optimise preventive measures and wound trauma management.

Methods

An advanced voxel model based on the Chinese Visible Human data was built. A digital human vulnerability model was established in combination with wound reconstruction and vulnerability assessment rules, in which wound penetration profiles were obtained by recreating the penetration of projectiles into ballistic gelatin. An effectiveness evaluation method of bullet penetration using the Abbreviated Injury Scale (AIS) was developed and solved using the Monte Carlo sampling method.

Results

The effectiveness of rifle bullets was demonstrated to increase with increasing velocity in the range of 300–700 m/s. When imparting the same energy, the effectiveness of the 5.56 mm bullet was higher than the 7.62 mm bullet in this model.

Conclusions

The superimposition of simulant penetration profiles produced from ballistic gelatin simulant has been used to predict wound tracts in damaged tissues. The authors recognise that determining clinical effectiveness based on the AIS scores alone without verification of outcome by review of clinical hospital records means that this technique should be seen more as a manner of comparing the effectiveness of bullets than an injury prediction model.

The experimental and numerical study of indirect effect of a rifle bullet on the bone

We study the transient indirect effect of a rifle bullet on bone in the gelatin-bone composite target experimentally and computationally. The process of a 56 type 7.62-mm rifle bullet penetrating the composite target has been simulated using numerical method. The experiment provided the criteria for verifying the correctness of the numerical model. We have obtained tomographic data of bone by CT scans, and also defined the bone as different layers by the gray scale to simulate its heterogeneity. The computed results are in good agreement with the experimental data. Effects of the impact velocity and bone location on damage caused to the composite target have also been studied. The numerical results imply the follows: When the velocity of bullet increases, the stress on bone also increases with the earlier pressure peak; When the bone is located in a certain distance from the trajectory, it will not be fractured, although it is affected by the stress wave.