Simulation on the Equivalent Relation Between Different Armour Plates Penetrated a Tungsten Sphere

Abstract

To research on the equivalent of perforating through LY12CZ aluminum alloy plates and 2π armor steel, based on the rule that the ultimate velocity, the penetration process of tungsten sphere into LY12CZ aluminum alloy plate and 2π armor steel plate was simulated with LS-DYNA finite element code, the numerical results corresponded well to previous experimental observation. The expression between LY12CZ aluminum alloy plate and 2π armor steel plate impacted by a tungsten sphere was presented through analyzing the numerical results. Introduction A lot of experiments often were required to target vulnerability research, and a lot of time and cost to adopt the whole true experiment, if the various armor protection level could be substituted by equivalent target, a lot of the experimental expenses and costs will be saved. In view of the two common armor materials, the protection level of aluminum alloy was equivalent by standard homogeneous steel. Numerical simulation is one of the main means of this kind of problem, It can greatly save the cost and shorten the research period by means of numerical simulation and the experimental correction[1]. Based on the principle of the equal ultimate velocity, the numerical simulation was used to the aluminum alloy target and the homogeneous target penetrated by the fragment through the finite element software LS-DYNA, and the equivalent relations of the aluminum alloy target and the homogeneous steel target was preliminary study. Equivalence Principle The two kinds of principle can be chosen for the equivalent of the plate impacted by fragment: the ultimate velocity method and the residual penetration method. From the evaluation of the power of ammunition, the ultimate velocity method was chosen, from the evaluation of the ability of target anti-damage, the residual penetration method was generally chosen. The ultimate velocity method was selected in this paper. The H1 thickness of aluminum alloy target and the H2 thickness of homogeneous steel target was penetrated by spherical fragment, and the same V50 of ultimate velocity was obtained on two kinds of target, so the H1 thickness of aluminum alloy target and the H2 thickness of homogeneous target was equivalent. The equivalent diagram of aluminum alloy target and homogeneous target as shown in Fig.1. International Conference on Materials, Environmental and Biological Engineering (MEBE 2015) © 2015. The authors Published by Atlantis Press 404 Spherical fragment H1 Homogeneous steel H2 Aluminum alloy Fig. 1 Equivalent diagram of aluminum alloy target and homogeneous target Numerical simulation Geometric modeling Experiment for reference to construct equivalent target model, material and size of fragment based on the literature[2], and combining the model shown in Fig. 1: (a)Target model: the materials of spherical fragment was tungsten alloy, the diameter was 10mm; The materials of plate was LY12CZ aluminum, the size was 100mm×100mm×10mm; (b)Equivalent target model: the size and material of fragment was the same as the target model, the materials of the plate was 2π armor steel, the size was 100mm×100mm×6mm. The constitutive model of fragment was Plastic_Kinematic[3], and the LY12CZ aluminum alloy and 2π armor steel was Johnson_Cook[3]. The symmetric plane was applied by boundary conditions, and a quarter of the overall model was used calculated based on the symmetry of the model. The nonreflect boundary condition was applied on the border around based on ignored the influence of boundary of stress wave. The meshing model was adopted by the 3d Solid164, and the target contact part of the unit was fine in order to reduce the computing time. The finite element calculation model was shown in Fig. 2. (a) Target model (b) Equivalent target model Fig. 2 Finite element model of calculation Results and analysis of simulation The 10mm diameter spherical tungsten alloy fragment with 440 m/s and the 450 m/s vertically impacted on 6mm thickness armor steel plates, the curve and the impact process of the fragment velocity as shown in Fig. 3 and Fig. 4. Fig. 3 State and velocity curve of spherical tungsten alloy fragment vertically impacted on 6mm thickness armor steel at 440m/s