Research On The Ballistic Impact Behavior And Configuration Of Ceramic Faced Composite Armor

Air weapons are playing an increasingly important role in modern warfare.But with the development of the ground air defense forces,the improvement of military aircraft survivability when subjected to ground fire threatened has become a concern for many counties.To ensure the safety during flight,the structure integrity should be maintained,and the main airframe should have sufficient impact resistance.Lightweight armor systems can efficiently improve the maneuverability,attack ability and survivability of aircrafts,and have become a trend for bulletproof armor system.The armor structure applied in the aircraft needs not only the good performance of anti-impact,but also to meet some special request such as aerodynamics and load transfer,as well as to satisfy the weight constraint.Traditional single material armor can not fit for this application,so a three layer configuration is designed in which a ceramic layer works as an energy absorption and dissipation layer,a carbon fiber layer works as a support layer and also a load transfer layer,and a UHMWPE layer works as a flexible layer to absorb the residual energy of the projectile.This configuration can effectively improve the anti-impact ability,and also achieve a structure/function integration design at the expense of smaller weight.This dissertation finishes the following works:1)The calculation procedures of impact dynamics are established utilizing the finite element method.Based on the classical theory of impact dynamics,the theoretical method are given to solve the problems during the impact process of the ceramic faced composite armor,which is a foreshadowing for the design of high anti-penetration armor design and analysis.2)The constitutive model subroutines are developed specifically for UHWMPE base on the hybrid model,improved the applicability of generalized software package.For the most commonly used materials for composite armor applications,the constitutive models are described as well as the damage criteria and equation of states.Performance data are also given according to experiments and reference.3)Preliminary armor configurations are designed,and the ballistic velocity limitation and impact resistance are implemented by ballistic test.Also,based on the constitutive models and parameters the finite element models using LS-DYNA code are built to simulate the ballistic test.The result shows a good consistency.This model is suit for impact analysis of multi-layered armor construction,which insured the calculation efficiency with the accuracy of the premise,and also laid the groundwork for the further optimization.4)Satisfactory results of the armor response simulation subject to blast wave load are obtained by two ways.The armor response subject to another threat,blast wave load,is analyzed based on the CJ theory of the blast wave.The description methods are given in two ways,the EOS method and the Conwep method.Both of the methods are utilized to build the FEM model for test the blast wave impact on composite armors.The results are compared using the deformation-time curve of the armor structure and are consistent in both tendency and values,which implies the future potential for HEI simulation.5)The optimized stacking sequence precondition for the best anti-penetration performance are established,and thus the stacking sequence optimization is accomplished,which improved the efficiency of the armor construction optimization.For a multi-layered composite armor,the ballistic limit velocity is solved using kinematics theory by structure response analysis of penetration process.With a given areal density,the best impact resistance is obtained and proved by numerical example,which reduce the computation quantity dramatically for the optimization of multi-layered composite armor construction.6)The stacking thickness optimization process is improved by introducing the metamodel based optimization method.Using the parametric finite element model of composite armor,under the condition of the same layer arrangement,the final lightest configuration was find out which can support the high speed impact load and HEI blast wave load,which achieves the high anti-penetration design for aircraft armor.Under the same projectile impact loading condition,compared with the traditional armor steel,the optimized design configuration has an areal density reduction of more than 40%.Target on the research of the composite armor,the analysis and simulation is carried out in this dissertation for the armor response subject to two kinds of loads.An optimized configuration is designed which has high anti-penetration and anti blast wave characteristics.The results and engineering method could be an important reference for the improvement of armor structures.