Investigation On Mechanisms Of Ceramic Composite Target Under Noncentral Impact Of 30mm Projectile

The process and mechanisms of ceramic/steel composite target impacted by 30mm projectile were investigated by experiment and numerical simulation, emphasized the ballistic performance and mechanisms of the composite target.under noncentral impact condition. The main contents and innovative works include:(1)The penetration process of ceramic/metal composite target under noncentral impacted was investigated by numerical simulation, the penetration process involves three stages: interface defeat, vertical penetration and oblique penetration. The oblique penetration can be re-divided into three stages: the projectile penetrations ceramic cone, the ceramic cone obtains the same velocity of the projectile, the residual projectile and the ceramic cone impact backing plate.(2)The main mechanisms of composite/steel target with three-dimensional constraints against penetration involve: energy dissipation due to peojectle ablation and plastic deformation of backing plate, and deflexion of projectile. Projectile ablation mainly happen in interface defeat, vertical penetration and the stage in which projectile penetrations ceramic cone. The non-symmetrical resistance due to the outward deformation of the side plate induces obliqueness of projectile which mainly hanppen in the oblique penetration and has important influence on the residual penetration ability. Energy dissipation due to plastic deformation of backing plate mainly happen in oblique penetration.(3)The influence of impact point on the ballistic performance and mechanisms is studied. The target can be divived into three subarea based on the distributing of limit velocity and the penetration characteristic between projectile and target: central subarea (e/a≤0.3), eccentricity subarea (0.30.4). The ballistic performance of central subarea is best, the next is eccentricity subarea, the edge subarea is worst, the width of edge subarea is 11mm. The effective protective area of target with hc /hs =7.5 and h f=6mm is e/a≤0.3. The durative time of interface defeat, the mass of projectile ablation and the energy dissipation of backing plate all decrease with the increase of e/a; The impact point has important influence on the shape of ceramic cone, the spread mode of crack and the crash area of ceramic plate.(4)The influence of target configuration on the ballistic performance and mechanisms is studied. The best hc /hs of target with h f=6mm and area densityρ=256.06kg/m2 is 4, the effective protective area is e/a≤0.25. hc /hs has little influence on the deflexion of projectile, and has important influence on the energy dissipation of backing plate. The projectile ablation of target with hc /hs =2 is least, and has little change with the change of e/a. The projectile ablation of target with hc /hs =4, 6and 7.5 is adjacent, and has biggish change with the change of e/a. The best h fof target with hc /hs =4 and the length of ceramic plate l =110mm is 10-12mm, the effective protective area is e/a≤0.3. h fhas little influence on the deflexion of projectile in the central subarea. The deflexion of projectile in the eccentricity subarea and edge subarea decrease with the increase of h f. The energy dissipation of backing plate increase with the increase of h f. The projectile ablation of target is best when h f=12mm.