| The blast wave will cause great damage to the armor structure,so the anti blast ability has always been the main tactical and technical index of the armor structure.With the rapid development of the composite armor structure,the application of polyurea in the composite armor structure is an important research direction for the majority of researchers in recent years.In this paper,the design method of anti explosion structure of polyurea armor is taken as the research object,and the factors influencing the structural response and anti explosion ability are obtained from different angles.In different circumstances,the factors are analyzed in detail,and the relationship between their anti explosion ability and structural response is obtained.Finally,the design method and main process of polyurea armor structure are proposed,which can provide some reference value and technical support for the design of polyurea armor structure.The main research work and conclusions of this paper can be summarized as follows:(1)Based on the theoretical analysis,starting from the direction of external environment to internal mechanism,the dynamic response and stress wave propagation of plate structure under the action of explosion shock wave in composite structure are analyzed.Several factors related to the anti explosion ability and dynamic response of composite structure are obtained.It is concluded that the combination style and thickness of composite structure are the internal factors affecting the anti explosion ability and dynamic response of structure Factors,charge amount or detonation distance are external factors that affect the dynamic response of the structure.(2)Verify the feasibility and effectiveness of the numerical simulation method ofAUTODYN software.The numerical simulation of Explosion Response of shock wave,steel structure and polyurea steel composite structure is carried out from three directions respectively,and then compared with the theoretical formula or experimental data,the error of numerical results is about 10%,which proves that AUTODYN software is suitable for the research work of this paper,and the material parameters and numerical simulation process show good accuracy and authenticity.(3)The damage process of composite structure under shock wave is simulated by means of numerical simulation.The anti explosion ability of different composite structure types is studied from two directions of different structure styles and number of medium layers.The following conclusions are obtained:(1)For different structures,when the polyurea layer is in the position of the explosion face in the composite structure,the anti explosion ability of the structure is lower,and when it is in the position of the back of the explosion face,the anti explosion ability of the structure is higher.For the structural style,BB and JX structures have relatively good anti explosion ability,while SM and Yb structures are slightly weaker.The four basic structural styles are JX,BB,SM and Yb from high to low.(2)To a certain extent,increasing the number of dielectric layers is helpful to enhance the anti explosion ability of the structure.But the number of medium layers is too much,the anti explosion ability of the structure is not significantly improved,and some structures even cause serious damage.When the number of medium layers is no more than four,the overall structure shows relatively high anti explosion ability.(4)The structure of BB and JX was simulated under the same surface density,the thickness of polyurea layer and the intensity of shock wave.The results are as follows:(1)Under the condition of the same surface density,compared with the pure steel structure,the anti explosion ability of BB structure has no obvious enhancement.JX structure is helpful to improve the anti explosion ability of the structure.In addition,when the thickness of the steel structure at the front and back of JX structure is the same,the antiexplosion ability of the structure is better.The thickness of the steel structure on the blasting face of JX can be increased appropriately,and should not be too thin,and the steel structure on the back should not be too thick.The thickness of polyurea layer should not be too large.(2)For the thickness of polyurea layer,there is a linear relationship between the response of composite structure and the thickness of polyurea layer.To a certain extent,with the increase of the thickness of polyurea layer,the anti explosion ability of the structure is also improved correspondingly,but the too thick polyurea layer is not helpful to improve the anti explosion ability.The thickness of polyurea layer is 12 mm when the anti explosion ability of BB and JX structures is optimized.(3)For the relationship between the response of composite structure and the strength of shock wave,with the increase of the peak value of shock wave overpressure,the range of the increase of the structure response gradually becomes larger and the damage to the structure is larger.The relationship between the deflection of structure deformation and the peak value of shock wave overpressure can be expressed by a function of cubic polynomial.(5)The structural design method of polyurea armor is summarized tentatively.The following process can be used for structural design:(1)Determination of explosion shock wave load;(2)determination of protection performance grade and protection safety criterion;(3)determination of structural design scheme and parameters;(4)connection treatment between different media layers;(5)verification of numerical simulation or test. |
