With the rapid development of science and technology and the substantial increase in the lethality of weapons,modern warfare has more and more stringent requirements on the protection and maneuverability of armored vehicle,so the need for armor materials with higher ballistic performance and light weight has become more and more urgent.Compared with traditional metal armor,7B52 laminate has lower density,better plasticity,higher specific strength,strong designability and better energy absorption.It can adapt to complex battlefield environments and can significantly improve survivability of armored vehicle.At present,there are few studies on the mechanical behavior and ballistic performance of 7B52 laminate.Under this background,the main researches carried out in this paper are as follows:The static-dynamic experiments of 7B52 laminate and 7A62,7A01,7A52 aluminum alloys were carried out,and their stress-strain relationships and Johnson-Cook constitutive models were obtained.The 7B52 laminate and 7A62 aluminum alloy have strong sensitivity to the strain rate,but as the strain rate increases,the strain rate sensitivity decreases;while the7A01 and 7A52 aluminum alloys have lower strain rate sensitivity;Under high-speed impact load,the ductility of the 7B52 laminate is 67% and 26% higher than that of the 7A62 and7A52 aluminum alloys,respectively,and the strength of the 7A01 aluminum alloy is increased by 72%;The interface with the intermediate layer 7A01 is damaged first,and the shear band is formed in the 7A52 soft layer;under quasi-static compression,the energy absorption of the 7B52 laminate is 131% higher than that of the 7A62 aluminum alloy,and under the impact load of 0.25 MPa,the energy absorption is improved 54%,and under the impact loads of 0.45 MPa and 0.65 MPa,the energy absorption levels of the two are close.The quasi-static compression tests of 7B52 laminate,7A62,7A01 and 7A52 aluminum alloys were simulated by ABAQUS finite element analysis software,and the stress-strain relationships of the four materials were obtained and compared with the experimental results.ABAQUS software was used to simulate the SHPB dynamic compression test of 7B52 laminate.The stress-strain relationship of 7B52 laminate and the macroscopic appearance of7B52 laminate under different impact loads were obtained.The numerical simulation results are basically consistent with the experimental results,which verifies the validity of johnsonCook constitutive model and its model parameters.Johnson-cook damage fracture models of7A62,7A01 and 7A52 aluminum alloys were determined by quasi-static tensile tests at room temperature and high temperature and dynamic compression tests by SHPB.ABAQUS is used to numerically simulate the process of bullet impacting the 7B52 laminate,and the R-I model of the target plate is established.This model can predict the residual velocity of the projectile after impacting the target plate at a certain initial speed,which provides a theory for studying the ballistic performance of the target plate.The damage forms of the target plate include the target plate forming lip,bulging,and plastic cracking;the damage principle of the target plate is that the initial kinetic energy of the projectile is converted into the thermal energy and the residual kinetic energy of the projectile target system,the plastic deformation energy consumption and the ductile hole expansion energy consumption of the target plate,in the process of energy conversion,which causes changes in the shape of the target plate,and at the same time,the variables SDEG,TRIAX,and PEEQ related to material failure also change;Based on the method of response surface optimization,the structure of the 7B52 laminate is optimized,and the optimal layer thickness ratio is determined.The energy absorption can be increased by 7.14% at the current level.The research provides a reference for the structural optimization of the 7B52 laminate,and provides theoretical support for the protection of armored vehicle. |