Bulletproof experimental materials and testing instruments and methods

           The basic specifications of the target plate materials used in this chapter are shown in Table 1.

         In Table 1, CT736 fabric is relatively thick and mainly used for composite material processing. CT709 is relatively thin and is mainly used for body armor processing. Both are products of the Dutch Akzo Nobel company. Spectra Shield Plus LCR (referred to as yellow film) and Glod Flex (referred to as white film) are products of Allied Signal Company (now the Performance Fiber Division of Honeywell Company in the United States). It is a thermoplastic matrix ultra-high molecular weight polyethylene fiber orthogonal lamination composite material. The matrix content is about 25-30%, and the resin is hexene or hexyl vinyl ester. The resin matrix used in composite laminates is thermoplastic polyvinyl butyral (PVB) modified phenolic resin. By controlling the amount of PVB added, the toughness and bonding properties of the phenolic resin itself can be improved. The specific formula is not given here due to technical confidentiality reasons.

 

Schematic diagram of V50 test device

Schematic diagram of target plate sample clamping device

         The sample is fixed on all sides and the sample area is 30cmX30cm.The V50 test device consists of a missile body, a missile launcher, a speed measuring device (consisting of two trigger devices and a counter), a target plate clamping device and a penetration verification device. The trigger device can be composed of a photoelectric screen or an originally insulated circuit contact screen, which triggers the counter by opening or closing the circuit when the projectile passes.

        V50 is a method of expressing the ballistic limit of target material. The ballistic limit is used to characterize the ballistic resistance of the target material (a measure of the material's ability to intercept or reduce the impact speed and quality of the projectile). Ballistic limits can also be represented by V0 and V100. V0 is the maximum speed when no penetration occurs, V100 is the lowest speed when complete penetration occurs, and V0 is the speed when the probability of penetration and non-penetration are 50% respectively. The average speed of at least two partial penetrations and two complete penetrations is used for specific measurements. There are also four-, six- and ten-round ballistic limits, which are the average velocities at which four (six or ten) rounds partially penetrate and four (six or ten) rounds completely penetrate. The speed used in averaging cannot exceed a certain speed range. The commonly used speed ranges are 18, 27, 30 and 38m/s respectively.

       At present, China has not promulgated testing standards for missile body V50. The test is conducted in accordance with the latest standard of the US Department of Defense MIL-STD-662F to simulate fragmentation V50 testing. Six rounds of V50 are used, and the speed range does not exceed 38m/s. For the bullet V50 test, it basically refers to MIL-STD-662F and the NIJ 0101.04 standard of the US Department of Justice, and uses ten rounds of V50. When shooting, the speed increase or decrease of 15m/s or 30m/s is basically used to change the bullet speed to obtain partial or complete penetration shooting results. Whether it is penetrated is observed by the verification board (0.05mm thick aluminum plate) (judged by whether the 60-watt bulb close to the verification board is light-transmissive).