Numerical Simulation Analysis Of Projectile Penetration Into Reinforced Concrete Multi-layer Target

In the military field,protective measures have always been a hot topic.The penetration of projectile into the multi-story reinforced concrete target plate is the focus of penetration problems and it is also an extremely complex issue.In this paper,the ANSYS/LS-DYNA software was used to verify the experiment about projectile oblique penetration of four layers of reinforced concrete target.Based on the model,the effect of projectile's initial dip angle and initial angle of attack on the penetration was studied,as well as the effect of the initial velocity,target thickness,target spacing and initial dip angle on the projectile penetration with angle of attack.The results showed that:(1)When initial dip angle of projectile is within 20 degrees,the maximum deflection angle of the projectile is only 1.23 degrees during the penetration process.When the dip angle is above 25 degrees,the maximum deflection angle can reach 6.2 degrees.When the initial dip is within the range of 10 to 30 degrees,the x-axis(horizontal direction)velocity of the projectile decreases almost linearly.(2)When the angle of attack is within the range of 1-5 degrees,the deflection angle of projectile increased about 20%for each increase of 1 degree.When projectile penetrates the first two layers of target plate,the maximum difference of the residual velocity in the x-axis direction between projectiles at different angles of attack is only 3m/s.The greater initial angle of attack,the faster the x-axis velocity of the projectile decreases.According to the magnitude of the velocity reduction,the attack angle can be divided into 1-3 degrees and 3-5 degrees.(3)When the projectile penetrates at an initial angle of attack of 1 degree,the deflection angle,which decreases with the increase of speed,increases with the increase of the thickness as well as the target plate spacing.The velocity drop of the projectile in the direction of x-axis decreases with the increase of velocity.It also increases with the increase of thickness as well as the target plate spacing.(4)When the initial dip angle of projectile was 20 degrees,the penetration effect under different attack angles was analyzed.The results showed that:When the dip angle promotes the deflection of projectile angle of attack,the larger angle of attack,the more obvious promotion effect.When the dip angle restricts the deflection of projectile angle of attack,the greater angle of attack,the smaller inhibition effect.(5)The BP neural network model based on genetic algorithm was established(GA-BP network model).Using above calculation data to train the network model,we could get a network model which can accurately predict the remaining velocity and attitude of projectile in a certain range.According to the failure effect of actual penetration,the model was optimized by taking the attitude angle of projectile reaching 60 degrees in process of penetration as the prediction limit.Finally,the model of penetration prediction considering the failure effect was obtained.