| With the development of amti-armor weapons and special arms, the battle environment has became a more seriously hazard to shielding structures, especially to armored vehicles. The most efficiency armor would have such advantages as bulletproof ability, radiation protection, biochemical weapons protection, debris shielding, tamper detection, high mobility and portability and so on. Compared with traditional metallic armors, the light weight composite armors have many superiorities like light weight, thin in depth, high strength and excellent designability. So the composite armors have effective battlefield survivability and can satisfied complex battle environments. In recent years, composite armors have taken place of massive homogeneous armors.Layered composite structure is a typical pattern of composite armor. Double layered metallic composite armor, ceramic/metallic composite armor and three layered hard/soft/hard composite armor are all buildup by different materials with various modes of connection. So far, the investigation of layered structures are mainly focused on its mechanical responses under high velocity penetration and damage processes. However studies on dynamic mechanical properties and stress wave propagation processes for layered structures are less in open literatures. In addition, there has less achievements on dynamic fragmentation of ceramic materials which are the key part for composite armors. To investigate these problems would have an effective and theoretical guidance values on armor designation. Based on the background mentioned above, this paper firstly investigates the dynamic mechanical properties for mono-materials which can be formed to layered structures; based on the experimental results, different constitutive equation parameters and a modified Rivilin model for rubber materials are published; these constitutive models are used to investigate the stress uniformity inside the specimens.Based on the results of mono-layered materials, the dynamic responses for double metallic structure, ceramic/metallic double layered structure and hard/soft/hard three layered structure are investigated; the plastic deformation influences on stress field distribution; different wave impedance of soft material, interface glue, rubber thicknesses and input stress wave shapes influence on stress wave propagation. At last, dynamic damage evolution and fragmentation patterns are investigated for both mono-layer AD95 ceramic and multi-layered AD95 ceramic structures. The investigation contents of this paper show below:Firstly, design a PVDF stress gauge to capture the stress profile in SHPB experiment, and use LS-DYNA software to simulate the SHPB process. In order to expand the experiment method, a self-made PVDF stress gauge was used to monitor the stress variety for both sides of the specimen; the dynamic response characteristics was analyzed; the influences of resistances, stress concentration, thermal viscosity effect, friction effect, multi-impact were investigated; finally a PVDF gauge with suitable sensitive area was developed for SHPB experiment and dynamic calibration parameter under 0MPa~420MPa was published; in order to investigated the stress wave inside the specimen, a simulated method use LS-DYNA was introduced, the numerical method was validated by comparing the numerical and experimental results.Secondly, the dynamic mechanical properties of mono-layer material was investigated by using SHPB experiments. Based on the experimental results, the stress uniformity inside the specimen was investigated for each mono-material, dynamic deformation process and mechanism of carbon black rubber, silicone rubber and foam rubber was also discussed; the constitutive parameters and modified Rivilin model was obtained, these parameters were validated by comparing the experimental and numerical results; by using the numerical simulation, stress field pattern of each mono-material was discussed.Thirdly, by using a combine method of both experiment and simulation to investigate the stress wave propagation mechanism in double-layered structure. Based on the experimental and simulation results, the stress field variety under different impact velocity in metal/metal and ceramic/metal double layered structure was investigated; the influence of plastic deformation to stress distribution was discussed; the effect of metal plasticity and tangential modulus were studied for the influence of stress propagation.Fourthly, by using a combine method of both experiment and simulation to investigate the stress wave propagation mechanism in tri-layered structure. Based on the experimental and simulation results, the stress wave attenuation, oscillation and distribution were analyzed, energy absorption capability and energy absorption efficiency were discussed for tri-layered structures. In addition, the influence between interface glue, rubber thicknesses, input stress wave shapes and stress wave propagation process were also studied.Fifthly, by using a combine method of both experiment and simulation to investigate dynamic fragmentation patterns and damage evolution processes for mono-layer AD95 ceramic, double-layered and tri-layered structures. The variety between material compression strength, critical strain, damage parameter and strain rate were discussed; Johnson-Holmquist II parameters of AD95 Al2O3 ceramic were deduced; dynamic damage evolution and fragmentation patterns were investigated by numerical simulation. Comparing with mono-layer ceramic, the double-layered structure had a less compression strength and by adding a soft material interface, the structure can be well protected.The result of this paper is a basic technical knowledge for dynamic response of different kinds of mono-layer materials and stress wave propagation mechanism in multi-layered structures. The results can provide the basic idea to develop the newly multi-layered shielding system and has an effective and theoretical guidance values to advanced armor system.
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