Study on Behind Helmet Blunt Trauma Caused by High-Speed Bullet

Abstract

The mechanism of Behind Helmet Blunt Trauma (BHBT) caused by a high-speed bullet is difficult to understand. At present, there is still a lack of corresponding parameters and test methods to evaluate this damage effectively. The purpose of the current study is therefore to investigate the response of the human skull and brain tissue under the loading of a bullet impacting a bullet-proof helmet, with the effects of impact direction, impact speed, and impactor structure being considered. A human brain finite element model which can accurately reconstruct the anatomical structures of the scalp, skull, brain tissue, etc., and can realistically reflect the biomechanical response of the brain under high impact speed was employed in this study. The responses of Back Face Deformation (BFD), brain displacement, skull stress, and dura mater pressure were extracted from simulations as the parameters reflecting BHBT risk, and the relationships between BHBT and bullet-proof equipment structure and performance were also investigated. The simulation results show that the frontal impact of the skull produces the largest amount of BFD, and when the impact directions are from the side, the skull stress is about twice higher than other directions. As the impact velocity increases, BFD, brain displacement, skull stress, and dura mater pressure increase. The brain damage caused by different structural bullet bodies is different under the condition of the same kinetic energy. The skull stress caused by the handgun bullet is the largest. The findings indicate that when a bullet impacts on the bullet-proof helmet, it has a higher probability of causing brain displacement and intracranial high pressure. The research results can provide a reference value for helmet optimization design and antielasticity evaluation and provide the theoretical basis for protection and rescue.

Mechanical analysis of helmeted headforms under ballistic impact with implications in performance evaluation of ballistic helmets

“…Higher peak values of various biomechanical parameters in the frontal orientation are attributed to the larger curvature, relatively smaller surface area, relatively smaller standoff distance between the interior of the helmet shell and the headform. This observation is consistent with the finding in the literature (Tan et al, 2012;Pasquali and Gaudenzi, 2017;Palta et al, 2018;Cai et al, 2020). Palta et al (2018) observed the orientation-dependent BFD response in a computational model of ACH mounted on the rigid headform.…”

“…The findings reported in this work are consistent with the finding in the literature. The BFD values obtained for headforms I and II (Table 2 a, b; Figure 6) are consistent with BFD values obtained in various computational and experimental investigations (Li et al, 2015;Rodríguez-Millán et al, 2016;Miranda-Vicario et al, 2018;Palta et al, 2018;Cai et al, 2020). Rodríguez-Millán et al (2016), using experiments and computational modeling, studied the response of rigid headform with witness material (i.e., R.P.…”

“…They obtained the BFD of 8-12 mm for front and back orientations and 4-6 mm for left and right orientations using the 9 mm FMJ bullet with a velocity of 300-380 m/sec. Cai et al (2020) measured BFD in ACH equipped computational head model using a 9 mm bullet with a velocity of 400-460 m/sec. They found the BFD values 10-13 mm in front, back, left, right, and crown orientation.…”

Study on protective performance and gradient optimization of helmet foam liner under bullet impact

“…2 a. The brain pressures, skull responses and the brain skull relative displacements have been verified refer to the relevant literature 27 – 29 , the material properties of bones and brain tissue are shown in Tables 2 and 3 . It can be used to study the dynamic response of the brain under the impact of rifle bullets and conduct injury analysis.…”

Evaluation of Combat Helmet Behavior under Blunt Impact

“…However, it is not a trivial task to improve the protective performance of a combat helmet without losing the real purpose of using composite materials, which is a decrease in weight. Traditionally, combat helmets have to be subjected to ballistic standards such as STANAG 2920 [5] or NIJ 0106.01 [6] and, consequently, they are analyzed at high impact velocities for the different ammunition [7][8][9][10][11][12], also under blast loadings [13][14][15][16][17][18]. However, the military industry has not focused on analyzing the Appl.…”