Development And Research On Textile Composites Of Anti-low Velocity Impact

In recent years, along with the increasing of high-level urbanization process, high altitude parabolic become metropolis ills may harm others; Traffic accidents of collision, mechanical impact in the process of project implementation, and production and processing of flying debris, such phenomenon produces imperceptible of penetrability damage. Therefore, for human safety protection of the individual protective equipment put forward higher and higher requirements.The traditional single material cannot meet the requirement, composite material is a significant trend in the development of the current material. Among them, the composite material has two meanings, one for the composite material, its design is based on superposition effect, by superposition of different material properties or complement each other, complementary advantages make the original component material, composite material after get a distinctive and better performance than the components materials. Secondly, composite materials, the various components separately after processing are combined, according to different material of single play its biggest advantage again together as a whole. For textile composites in the field of protection existing research is more about this priorities topic research in low speed impact protection of textile composite materials research and development.Protective material for impact load power of each component in diffusion, buffer and consumption is the key of the research protection low-velocity impact of composite materials. With the impact of the speed and quality the impact and collision of content to another object, from the physical sense, is the kinetic energy is converted into other energy(such as heat energy, elastic potential energy, etc.). This topic research main line for the use of high performance fiber materials spread and impact energy of the first plane, expand the area of impact loading, reduce the peak value of impact; Through three-dimensional interval fabric to cushion the impact energy, the impact energy greatly reduced; Final comprehensive consideration of viscoelastic material and the impact properties of partition, further research as a buffer layer of textile material for protective structure as a whole, thus will not directly and machine of high performance fiber weaving and knitting fabric between effective combination, such as reducing the peak value of impact at the same time, as far as possible to maintain peak acceleration time, thus guide for best low speed impact protection and the design principle of the composite materials.This topic research content has the following several aspects:(1) Organic glass with glass fiber and epoxy resin plate design and production to test the impact of stress wave transmission isotropic and anisotropic stress wave transmission characteristics of two kinds of material test platform, studying the characteristics of stress wave transmission, discussed under the condition of same thickness of glass fiber epoxy laminate and epoxy resin plate stress wave in the passing of time. Study under the same thickness of organic glass laminate and organic glass plate stress wave transmission time, stress wave transmission rate, analyses the reason of the difference. Anisotropic stress wave transfer speed higher than that of isotropic materials, the existence of the fiber material is advantageous to the stress wave horizontal transfer and diffusion. Laminated plate in the air layer interface is conducive to the formation of stress wave attenuation in the process of vertical transmission.(2) Based on shock response of a single material performance study of the single fiber knitting fabric, woven fabric and fiber reinforced composite material of stress wave transmission research and warp knitted fabric between the study of the relationship between viscoelasticity and impact performance, through the orthogonal experiment design different ways of organization structure and layer spacing and the warp knitting fabric are combined, choose high performance fiber fabric(without weft weaving cloth, machine, etc.) and combination of warp knitted space fabric and using the material stress wave transmission characteristics, peak area in order to reduce the impact, by increasing impact based on compression properties of warp knitted and damping characteristics as far as possible to reduce the peak, shortening the time of peak acceleration to maintain, make effective impact energy dissipation composite materials. And points out relationship of factors of the combination: organizational structure> layers> warp knitted fabric. Under the condition in this experiment, the best impact resistant textile material combinations is the four layers of ultra-high molecular weight polyethylene without weft cloth and viscoelastic ratio 3.65 of the warp knitted fabric combination.(3) Design and develop a test device for small quality high speed impact test environment which can up to 100m/s, and carries on the debugging, through a different impact speed control the compressed air pressure, it is concluded that the peak value of impact velocity and impact force function expression. Make sure small high-speed testing device can be controlled at the speed of 53m/s to take composite material experiment. Ultra-high molecular weight polyethylene without weft cloth with 25 layer and viscoelastic ratio 3.82 of the hexagonal mesh interval of the thickness of 10.5mm warp knitting fabric has good shock resistance, with smaller shocks to maintain peak acceleration time and residual impact, which is an verification of composite materials in low speed impact environment mechanism of the collocation of feasibility and the validity of the evaluation index.