Abstract:
The purpose of this research was to analyze the stress and deformation of stacked metal armor plates and to analyze their penetration resistance by the finite element method according to the NIJ level 3 standard by a 7.62x51mm bullet at a speed of 850 meters per second. ANSYS Explicit/Dynamic program was adopted to predict the damage behavior of 7075 T6 and 5083-H116 grade bulletproof aluminum armor plates. The finite element model was validated against the results of experimental firing with a genuine bullet. The important variables are the thickness of the aluminum plate and the number of stacked layers with the distance between the plates and without the distance between the plates. The 7.62x51 mm tungsten carbide
bullet was determined to have a damage pattern in accordance with the Johnson-Holmquist Failure Model (JH-1, JH-2). The armor plates were 30x30 cm in width and length. The property of AL-7075 T6 material conformed to the Steinberg-Guinan Strength, and that of the AL-5083-H116 material conformed to the Johnson-Cook Strength model. The results showed that selecting types of elements and dividing elements were the important factors affecting the analysis. The use of element division techniques was important as the element must be divided into a small size where the bullet hit the armor plate and there must not be too many lements in the area further away from the bullet. According to the design of AL-7075 and AL-5083-H116 aluminum plates, different thicknesses and distances between plates would affect their
penetration resistance. The variables that affected the extremely high penetration resistance were the armor plate thickness and the number of the armor plate layers, but the distance between the plates had a low impact on the penetration resistance