A measuring set for visualization of ballistic impact on soft armor

Abstract

This paper presents a dissipated force measuring set for testing of the soft body armor type II-A. This type of armor protects against 9 mm full metal jacketed round nose (FMJ RN) bullets, with nominal masses of 8.0 g, impacting at a minimum velocity of 341 m/s. The impact absorber area of the measuring set is about 25 in 2 (161.3 cm 2 ). The impact force is converted into electrical potential by the force transducers which are specially designed for this purpose. The designed transducer consists of two air cylinders connect to the modified air pressure switch where two permanent magnet bars are installed on the little piston inside the housing of the switch. Hall Effect sensor, which provides a linear output voltage and quick respond, is mounted between the magnetic bars in order to convert the moving distance of the magnetic bars into analog voltage as the transducer output. Then the analog output voltage is converted into digital signal by the Data Acquisition. LabView program is employed to control and process the obtained data from the data acquisition in order to record and plot the impact force in three dimensional shapes. The obtained results from the measuring set are compared to the standard testing method according to NIJ standard 0101.04 that employs Roma Plastilina No.1 clay. The experiments were carried on to measure the impact force from the gun fire and the satisfactory results are given and reported.