ИСТИНА

The processes of energy dissipation in woven barriers at a low-rate penetration are strongly influenced by friction [1]. As a result, the successful optimization of the ballistic efficiency of the woven protective layers should include the investigation of friction under the suitable loading conditions. A common approach to the determination of the friction parameters is based on the results of experiments of the yarn pullout from a fabric layer [2-3]. More realistic method involves the use of the experimental data of the woven layer pullout under the conditions of transversal compression [4]. We propose a further development of this approach. The new experimental equipment is designed for pulling out the fabric layer of the multilayer woven package under the transversal compression. The proposed device allows us to specify the compressive loads in a wide practice range. The integral characteristics of friction obtained as a result of experiment can be implemented in the numerical models of fracture. The geometrical parameters both of yarns (up to filaments) and of woven architecture were defined for several specimens of fabrics. Elastic moduli and strength limits of aramid yarns were determined. The required range of the transverse compression is estimated by the use of FE-modelling of impact loading of one- and four-layer protective plain-woven barriers. According to obtained estimations, the values of transversal compressive load in our tests vary from 200 N to 2000 N. On the base of the numerical modelling of the proposed experimental equipment the stress distribution uniformity in the middle fabric layer was investigated. The static and dynamic friction coefficients for plain weave aramid fabric were defined for the cases of textile-textile and textile-duralumin interfaces. 1. Mossakovsky P.A. Balandin V.V. Belyaev A.P. Belyakova T.A. Bragov A.M. Inyukhin A.V. Kostyreva L.A. Investigation dissipative factors in puncturing multilayered woven obstacles // Problems of strength and plasticity, 2015, vol. 77, № 4, pp. 385-392 (in Russian); 2. Bazhenov S. Dissipation of Energy by Bulletproof Aramid Fabric // Journal of Materials Science, 1997, vol. 32, №. 15, pp. 4167-4173; 3. Kirkwood K.M., Kirkwood J.E., Lee Y.S., Egres R.G., Wagner N.J., Wetzel E.D. Yarn Pull-Out as a mechanism for Dissipating Ballistic Impact Energy in Kevlar KM-2 Fabric // Textile Research Journal, 2004, vol. 74, pp. 920-928; 4. Martinez M. A., Navarro C., Cortes R., Rodriguez J. Friction and wear behaviour of Kevlar fabrics // Journal of Materials Science, 1993, № 28, pp. 1305-1311.