Study On Impact Resistance Of CFRP/Aluminum Foam Sandwich Structure

The aluminum foam sandwich structure has light weight,high specific strength,high specific stiffness and good energy absorption characteristics,and is widely used in many fields such as aerospace,shipbuilding and protection engineering.At present,there are relatively few studies on the aluminum foam sandwich structure with composite materials as the panel at home and abroad,and most of them focus on quasi-static mechanical properties.In this paper,the CFRP/aluminum foam sandwich structure is taken as the research object,and the failure mode and anti-elasticity under impact loading condition are studied by the combination of experiment and numerical simulation.The specific research contents and achievements are as follows:(1)The CFRP/aluminum foam sandwich structure was subjected to a ballistic impact test using a one-stage light gas gun loaded with a cylindrical flat-head projectile at an impact velocity between 100 m/s and 300 m/s.The failure mode of the sandwich structure was obtained.In the case where the target plate is completely penetrated,the front panel undergoes shear failure,and a circular sheet is cut off.The foamed aluminum core layer is shear perforated and a large amount of aluminum foam fragments are formed.The "cross" petal-shaped perforation damage occurs on the back surface of the rear panel.Compared with the single aluminum foam,the impact resistance of CFRP/foam aluminum sandwich structure against flat head projectile is significantly improved.The pressure time history during the impact process was obtained by PVDF piezoelectric sensor.The results show that the existence of the foamed aluminum core layer makes the sandwich structure have a strong attenuation effect on the impact load.(2)The impact resistance of CFRP/aluminum foam sandwich structure was numerically simulated by ABAQUS/Explicit software.The effects of impact parameters such as different initial velocity,different projectile shape and different angles(The angle between the direction of the ballistic direction and the normal direction of the target)on the impact resistance of CFRP/foam aluminum sandwich structure were studied.The numerical simulation results show that the kinetic energy loss of the projectile increases with the increase of the impact velocity in the speed range of 100?450m/s,and the elastic resistance of the sandwich structure is stronger.The shape of the projectile has a great influence on the impact resistance of the CFRP/aluminum foam sandwich structure,and its performance against flat head impact is stronger than that against ball impact.When the impact velocity is more than 300m/s,the shape of the projectile has little effect on the impact resistance of the CFRP/aluminum foam sandwich structure.Under different impact angle conditions,the impact resistance of CFRP/foam aluminum sandwich structure increases with the increase of the angle.