Modelowanie wielowarstwowych osłon balistycznych minimalizujących skutki udaru

Abstract

Soft ballistic packages are the main element of ballistic shields and are a vital protective layer protecting against fire from the firearms. Multilayer soft ballistic packages used in bulletproof vests provide protection against loss of health or even save lives of representatives of the social groups whose job is to ensure the lasting national security, maintain public order in the country and provide a sense of physical safety and security of property of the citizens. All representatives of these groups deserve the specialized and most innovative personal protection. The main aim of the foregoing doctoral thesis was to obtain an optimal textile structure of a ballistic shield minimizing the physiological effects of an impact. The thesis looks closer at the triaxial and biaxial structures adopting the two-step research methodology: numerical analysis, using Finite Element Method (FEM), and experimental verification in Ballistic Research Laboratory. First of all, numerical research – hitting 9x19 mm Parabellum FMJ bullet into the multilayered ballistic package was performed. This part resulted in the numerical analysis of the conception of replacing the fabricstructured 3D object by the homogenized 2D shell using different material models. The results of numerical research were verified experimentally in the ballistic tunnel. Packages consisted of 6, 12, 16, 18, 20, 22, 24, 30 layers of biaxial and triaxial KEVLAR 29 fabric. On the basis of the complete research results, it was found that the proposed conception of replacing the biaxial and triaxial fabric layer by the 2D shell will fully realize the established research plan. Particularly it was proved, that through the use of different material models for the researched textile structures it is possible to obtain similar ballistic effectiveness as in the case of real textile ballistic packages. In its further part the following paper describes the methodology of the research of soft ballistic packages using standard Roma No.1 substrate in accordance with the NIJ Standard 0101.06 and the proposed substrate Clear Ballistics Gel with characteristics similar to the tissues of the body. There were significant differences in the maximum deformation cone for the package of 30 layers of woven biaxial and triaxial KEVLAR 29, depending on the ballistic substrate applied. The vast difference in the volume of deformation of the package depending on the ballistic substrate illustrates the problem of the currently used not updated research methodology of personal protection. The use of ballistic gel as a professional ballistic substrate is reliably closer to the real conditions in which vests are used. Based on the results, it was found that if diversified ballistic substrate was applied there is a tendency for the triaxial fabric ballistic package to achieve less than the maximum deformation cone. The value is low compared to the biaxial fabric package as a result of the influence of the isotropic properties of the fabric. Medical consultations of the analyzed research problem allowed to state that the assessment of the potential effects of a ballistic trauma depends primarily on defining the anatomic location of the bullet hits. Depending on where the deformation takes place in may result in breaking of ribs, lung contusion, pleural parenchyma and in extreme cases can lead to pneumothorax or bleeding into the pleural cavity. For the package with lower deformation values the scale of internal injuries is reduced and may lead to health changes only. The last stage of the research was to determine the scale of physiological effects of a stroke during non-penetrative bullet hitting in ballistic shield. For this purpose, numerical research was conducted using the discrete model in the form of human body – a package of ballistic – projectile It was also a challenge to make a physical model of the human body having the most important internal organs: heart and lungs. As a result of numerical analysis and experiments, it was found that the structure of the triaxial textile enables to minimize the maximum deformation cone, and consequently reduces the physiological effects of the stroke. The ballistic package of the biaxial fabric, which is an anisotropic material, significant damage in the place of direct impact in the shock wave was observed. On the other hand, the ballistic package made of triaxial fabric shows the influence of isotropic properties meaning that the deformation may be spread over a larger area ensuring less serious deformation of the internal organs. On the basis of medical opinion it was concluded that the triaxial fabric ballistic package can minimize the occurrence of rupture of liver capsule and the emergence subcapsular hematoma and there is little likelihood of intestine or colon perforation. In the case of the analysis of the damage to the thoracic cavity it has been found that the multiaxial fabric package will help to minimize the occurrence of pneumothorax and the occurrence of the extensive hemorrhage of the lung along the ribs.