Research On Design And Anti-penetration Properties Of Ceramic Composite Armor Containing Aluminum Foam Wave-absorbing Layer

Performance of anti-armor weapons is getting more efficiency and comprehensive in modern wars. In order to meet the requirements of mobility and repellency on the battlefield, many military powers in the world are fully committed to obtaining composite armor with less mass and better ballistic performance. Ceramic composite armor are widely used for its superior performance, and ballistic property of ceramic composite armor added porous materials wave-absorbing layer has been given a lot of attention at home and abroad.As a kind of wave absorbing material, aluminum foam could attenuate shock wave intensity and delay shock wave arrival time by pore structure deformation during a collision. Aluminum foam could be thought to have the potential application value in armor protection. Recent studies suggest that ceramic composite armor containing aluminum foam wave-absorbing layer has excellent anti-penetration performance, but influences of layer assembling technology and layer structure parameters are even rare. In addition, the constitutive model and the corresponding parameters for objectively reflecting the mechanical properties of components are important input data for the anti-penetration performance evaluation of armor structure by numerical simulation. So far, aluminum foam generally has been thought as completely compressible material in its dynamic constitutive model, without considering the plastic Poisson ratio, existing big limitation.In the light of the background mentioned above, this paper is concerned with ceramic composite armor containing aluminum foam wave-absorbing layer. Using the methods of high speed impact experiment, numerical simulation, and theoretical analysis, on the basis of the constitutive model and the corresponding parameters of each monomer component materials especially aluminum foam, the anti-penetration performance of ceramic composite armor containing aluminum foam wave-absorbing layer affected by interfacial bonding between layers, circumferential restriction, layer structure parameters have been investigated, then establish the anti-penetration evaluation model. The main contents of this paper are showed below:Firstly, put forward the method of obtaining plastic Poisson ratio of cellular material, and set up a rate-dependent constitutive model of aluminum foam considering the plastic Poisson ratio. With reference to energy method formula of Taylor test presented by Hawkyard, use a non-linear function to describe the relationship between the relative density of plastic zone and axial strain under Taylor impact for porous material projectile, and then combined with the Taylor experiment the plastic Poisson ratio of porous material could be obtained, and aluminum foam as a typical example was analyzed. Based on quasi-static compression and dynamic compression methods, stress-strain relationship of aluminum foam under uniaxial compression was obtained. After that, based on the Deshpande-Fleck yield criterion, a rate-dependent constitutive model of aluminum foam considering the plastic poisson ratio was built and verified by aluminum foam Taylor experiments.Secondly, obtain the anti-penetration performance of ceramic/aluminum foam/metal composite armor influenced by interfacial bonding between layers and circumferential restriction, and reveal the mechanism. Damage characteristics of each layer under different interfacial bonding between layers and circumferential restriction could be got by experimental methods. The numerical simulation methods, validated by the typical high speed impact experiments, can be used to obtain ballistics limit velocity of the composite armor and attenuation characteristics of velocity, acceleration, kinetic energy of projectile in penetrating. Based on this, the influence mechanism of damage characteristics and the anti-penetration performance by interfacial bonding between layers and circumferential restriction of the composite armor was investigated. When the layer parameters of ceramic/aluminum foam/metal armor structure remains unchanged, the studies have shown that bonding ceramic plate with the facing bullet planes of aluminum foam or circumferential restriction of ceramic and aluminum foam plate limited crack propagation of ceramic plate and aluminum foam plate, enhanced energy consumption of armor structure, and improved the anti-penetration performance, but bonding the metal back panel with the back elastic surface of aluminum foam plate had the opposite effect by easily leading to bending fracture in advance of the ceramic plate and the foam plate.Thirdly, obtain the anti-penetration performance of ceramic/metal/aluminum foam/metal composite armor influenced by the structure parameters of metal plate and foam plate, and reveal penetrating characteristics of projectile. Numerical simulation method, validated by the typical high speed impact experiments, was used to obtain the ballistics limit velocity and characteristics of velocity, acceleration, kinetic energy, displacement of projectile of ceramic/metal/aluminum foam/metal composite armor in the penetration affected by the structure parameters of metal plate and foam plate. When the area density and the thickness of ceramic plate in ceramic/metal/ aluminum foam/metal armor structure keeping constant, the studies have shown that thickness of metal and aluminum foam plate was one of the major effective factors and give optimum region of thickness distribution, but porosity of aluminum foam became a secondary consideration for the anti-penetration performance of the composite armor.Fourly, based on the relationship energy consumption of each layered structure with "projectile target" basic parameters, an anti-penetration evaluation model was set up and used to discuss the optimum design for ceramic/metal/aluminum foam/metal composite armor. The penetration process could be divided into elements according to different damage modes of layered structure affected by the characteristics of layered materials of armor structure. Based on the research of the natural parameters of ceramic conoid by experiments, the ceramic plate, metal transition plate, the foam plate, the rear plate of layer energy consumption functions varied with "projectile target" basic parameters were established. Then, an anti-penetration evaluation model has been built and validated by the typical impacts and simulations. The anti-penetration evaluation model could be used to analyze the anti-penetration performance affected by the structure composition, and provided foundations for the optimum design of the composite armor.By all accounts, based on the research of a rate-dependent constitutive model of aluminum foam, the anti-penetration performance of the ceramic composite armor containing aluminum foam wave-absorbing layer under high speed impacts effected by interfacial bonding between layers, circumferential restriction, the structure parameters of metal and aluminum foam plate were systematically analyzed, then the anti-penetration evaluation model and the optimum design of the composite armor had been discussed. The results could provide a technical guidance for the design and application of advanced composite armor system.