Research On The Penetration Behavior Of The Novel-section Projectile

The research and development of high strength and toughness rod or new structures rod have been the focus and primary task of scholars and experts.For the purpose of improving the penetration performance of the rod from its structure,several novel-section projectiles are designed,researching on constitutive model parameters of rod and target materials is carried out,vertical penetration process of novel-section projectile is simulated,armor piercing test in shooting range is conducted in this thesis.The penetration performance and mechanism of the designed novel-section projectiles are analyzed and discussed systematically.The main research and conclusions are as follows:⑴ The constitutive model parameters of rod and target materials are studied.Through the static and dynamic uniaxial compression test,the values of A,B,n and C parameters in Johnsoncook constitutive model of tungsten alloy and RHA are obtained.For the parameters of tungsten alloy: A=650.65 MPa,B=1252.33 MPa,n=0.58979,C=0.075,and the parameters of RHA:A=785MPa,B=689MPa,n=0.435,C=0.036.In the dynamic compression test,the influence of shaper on the incident waveform is studied to ensure the dynamic stress balance and constant strain rate loading of the specimen in the SHPB test,and the influence rules of shaper diameter,thickness,striker bar length,striker bar velocity on the incident waveform are obtained.⑵ The vertical penetration process of three kinds of novel-section(triangle,square,cross)projectiles is simulated,and the study on the influence of cross-section dimension coefficient ?on penetration performance is carried out by simulation for the cruciform cross-section projectile which with the best penetration performance.The results show that,impact and compression make the rod material more prone to severe plastic deformation and failure along the edge.As a result of the “ mushroom like shape” at the head of the cruciform cross-section projectile is smaller and the fragments produced by the projectile and target are more easily discharged along the gap during the penetration,meanwhile,at the later stage of penetration,the velocity of triangular and square cross-section projectile drops faster than that of cross section projectile,the cruciform cross-section projectile has the best penetration performance.Furthermore,the shape of the crater tends to like a cross-section when ? ?31.85 and tends to be like a square-section when ? ?61.85.⑶ The vertical penetration test of 45# steel/ tungsten alloy material rod into semi-infinite target plate made by 45# steel and RHA is carried out.The experimental results show that,with equal area of cross-section,novel-section projectiles are designed in this thesis have higher penetration efficiency than the circular cross-section projectile.On the one hand,shear-failure of novel-section projectile is easy to occur,caused the head area of novel-section projectile is smaller than that of the circular section projectile during the process of penetration,thus,the“self-shaping” behavior reduced the penetration resistance of novel-section projectile.On the other hand,the debris produced by projectile and target are discharged along the gap,which further reduces the penetration resistance of the rod,so it has better penetration efficiency.The penetration performance of the novel-section projectile has been verified by the simulation and experiments,it is better than the traditional circular-section projectile under high impact velocity.The penetration rule and penetration mechanism are obtained by the simulation and experiments,which conducts the foundation theory for the further research on the novelsection projectile.