عنوان مقاله
طراحی بهینه مواد زره بدن با استفاده از سیال ضخیم کننده تنش
فهرست مطالب
مقدمه
مواد و روش ها
آزمایش مقاومت ضربه دینامیکی
نتایج و بحث
نتیجه گیری
بخشی از مقاله
برای بهبود قابلیت مرطوب شدن پارچه‌های Kevlar با STF ها، این پخش شدن‌ها قبل از استفاده بر روی پارچه‌هایKevlar با اتانول رقیق شده‌اند. رقیق کردن، ویسکوزیته و کشش سطحی STF ها را کاهش می‌دهد، بنابراین نفوذپذیری آن‌ها را به درون ساختار پارچه‌هایKevlar بهتر می‌کند. در بحث‌های زیر، نسبتSTF به الکل با عبارت نسبت حلال مشخص شده است.
کلمات کلیدی:
Optimal designing of soft body armour materials using shear thickening fluid Abhijit Majumdar ⇑ , Bhupendra Singh Butola, Ankita Srivastava Department of Textile Technology, Indian Institute of Technology, Delhi 110 016, India article info Article history: Received 24 August 2012 Accepted 15 October 2012 Available online 26 October 2012 abstract This paper deals with the optimal design of soft body armour materials by treating Kevlar (para-aramid) fabrics with silica nano-particle based shear thickening fluid (STF). Box and Behnken design of experiment (DOE) plan in conjunction with contour analysis has been used to study the effect of silica concentration, padding pressure and diluent: STF ratio (solvent ratio) on STF add-on% and impact energy absorption. Silica concentration, solvent ratio and square of solvent ratio were found to be statistically significant terms influencing the STF add-on% on Kevlar fabrics. On the other hand, silica concentration, padding pressure and the square of solvent ratio were the statistically significant terms influencing the impact energy absorption. Higher padding pressure enhances the impact energy absorption by the STF treated Kevlar fabrics although it does not influence the STF add-on% significantly. Higher STF add-on% is a necessary but not the sufficient condition for improving the impact resistance performance of Kevlar fabrics. 2012 Elsevier Ltd. All rights reserved. 1. Introduction Kevlar woven fabrics are often used for soft body armour applications. In soft body armours, approximately 20–50 layers of Kevlar fabric are used to stop a bullet fired by a shotgun or revolver. This makes the body armour heavy, inflexible and uncomfortable to the wearer. It is a challenge for the researchers and scientists to develop materials for soft body armour so that it remains light-weight, flexible and bullet-resistant. Application of shear thickening fluid (STF) enhances the impact resistance performance of the Kevlar fabric [1,2]. Shear thickening fluids are non-Newtonian fluids which show drastic increase in viscosity beyond a critical shear rate [3–7]. Thus, the liquid dispersion is transformed into a material with solid-like properties and thereby facilitating the impact energy absorption. Shear thickening is exhibited by the nano sized particles of certain materials (silica, calcium carbonate, poly methyl methacrylate, etc.) when they are dispersed in a career fluid. Shear thickening behavior is reversible, making the body armour flexible enough for normal mobility of the soldier. In the last decade, significant amount of research works have been done on the application of STF on Kevlar fabrics for improving the impact, puncture or stab resistance performances. Lee et al. [1,8], Kang et al. [9] and Srivastava et al. [10] have used silica nano-particles based STF to improve the impact resistance performance of Kevlar woven fabrics whereas Egres et al. [11] used it for enhancing the puncture resistance against hypodermic needles. Decker et al. [12] reported significant improvement in stab resistance performance during knife drop tower test. They found that the extent of fabric damage was less in case of STF treated Kevlar fabrics. Tan et al. [13] reported that the ballistic performance of aramid fabrics can be improved by impregnating it with a colloidal silica water suspension (SWS) of different particle concentrations. Wetzel et al. [14] also researched on the influence of particle shape anisotropy on the performance of STF treated Kevlar fabrics. They reported that as the aspect ratio of the particles increases, requirement of the solid volume fraction to reach the critical shear rate decreases. Kalman et al. [15] compared the STFs made with hard silica and softer PMMA (poly methyl methacrylate) particles for improving the impact resistance performance of Kevlar fabrics. They found that the STF based on PMMA exhibited less effective shear thickening as compared to STF based on hard silica particles. Thus silica based STF treated fabrics showed better ballistic resistance than that of PMMA based STF treated fabrics. Rosen et al. [16] used Kaolin clay (platelet like structure) dispersed in ethylene glycol as STF which improved the spike, stab and needle resistances. In recent researches, Hassan et al. [17,18] and Maufez et al. [19] have developed a sonochemical method for the synthesis of STF in a single step. They found that the spike resistance of Kevlar fabrics increased from 85 N to 573 N after the treatment with the STF. Park et al. [20,21] reported the effect of laminating sequence, fabric count and shot location on the impact performance of STF treated Kevlar fabrics. Optimisation of structure and properties of engineering materials is a very exciting domain of research. Various quantitative techniques like Design of Experiments [22], Taguchi [23,24], multicriteria decision making [25,26] and genetic algorithm [27] have been used by the researchers for modeling and optimisation of material properties. Although substantial amount of research has been done to improve the impact performance of Kevlar fabrics
