Research On The Damage Efficiency Of Shaped Charge To Warship Typical Target Plates

In order to improve the damage ability of ammunition to warship,the damage efficiency of annular shaped charge blast loading(Explosively Formed Projectile,EFP)to typical warship target plates(double-layer target plates and stiffened target plates)under water and shallow water was studied,based on researches of the formation mechanism of shaped charge jet,the destruction mode of shaped charge,factors that influence shaped charge effect and target plates structure of warships.A method coupled with euler method and Lagrangian method was applied,a model that can describe the damage efficiency of annular shaped charge to typical ship target plates was established(the vent hole size and penetration depth),and static explosion tests were conducted for verification.The principal research contents were as follows:(1)A annular shaped charge structures were designed:Q235 steel is chosen as the shell material of second annular shaped charge warhead.The diameter of the warhead is 100mm,the height is 100mm,the wall thickness of the warhead is 2mm.There is a 25mm diameter through hole in the center of end cover,for the purpose of installing booster pellet and the end cover thickness is 4.0mm.B explosive is used as the warhead charge,the charge mass is1.38kg,the charge height is 100mm,the charge diameter is 96mm,the charge density is1.68g/cm3 and melt casting is adopted as charge method.(2)mechanism of shaped charge jet,was 1/4 small-scale model test the destruction mode of shaped charge and factors that influence shaped charge effect.The first designed warhead has a diameter of 25mm,a height of 40mm,and a hole with a diameter of 7mm in the center for installation of No.8 commercial electric detonator.The shaped charge is composition B powder using compression charge method,with a charge mass of 40g,a charge height of25mm,a charge diameter of 40mm,and a charge density of 1.68g/cm~3.The material of shaped charge liner is red copper,which is surrounded by partial intercross section formed by material with a diameter of 9.8mm and 9.12mm,respectively.The size of the double-layer target plate for underwater explosion test is 500mm×500mm×3mm,and the size of frame is500mm×500mm×50mm.The first shaped charge underwater explosion test is against single-layer target plate and the result shows that the apertrue value of target is 166mm.And the second shaped charge underwater explosion test is against double-layer target plate.The apertrue value of first layer plate is 177mm while the inlet aperture value of second layer is20mm.(3)AUTODYN software was applied to establish a two-dimensional model of annular shaped charge penetrating underwater double-layer structure,CEL algorithm was selected and the annular shaped charge jet successfully penetrated the double layer structure.The simulation error of the first shaped charge underwater explosion test is 12.5%.And for the second explosion test,the error of the first layer and the second layer are 15.3%and 15.0%,respectively(4)JH-14C is selected as booster explosive,the diameter of grain is 25mm,the height is20mm,the charging density is 1.70g/cm3,and the charge mass is 16.68g.Red copper shaped charge liner is surrounded by partial intercross section formed by material with a diameter of48mm and 47.7mm,respectively.The target plate for static explosion test is a double-layer45#steel target with a size of 400mm×400mm×10mm and a 400mm×400mm×50mm aluminum target.As for stiffened plates,a 400mm×400mm×10mm 45#steel target is welded with 6 stiffened plates and 7 stiffened plates respectively and another 400mm×400mm×50mm aluminum target is also used.The first static explosion test is for a double-layer target plate without reinforcement:The inlet aperture of the first layer target is 75mm,the outlet aperture is 75mm while the inlet aperture of the second layer target is 91mm,and the outlet aperture is84mm.The second static explosion test is aimed at the double-layer target plate with stiffened structure:the first layer target has an inlet aperture of 75mm and an outlet aperture of 75mm.The second layer target has an inlet aperture of 90mm and an outlet aperture of 84mm.The third static explosion test is conducted for the double-layer target plate with reinforcement:the first layer target has an inlet aperture of 75mm,the outlet aperture of 75mm,and the second layer target has an inlet aperture of 83mm and the outlet aperture of 83mm.(5)AUTODYN software was also employed when establishing a three-dimensional model of annular shaped charge penetrating double-layer target plates under shallow water,then the penetration process of stiffening plates and stiffeners were simulated,and the annular shaped charge penetrated all three target plates.For the first static explosion test,the error of the front and back of the first layer target is 8.0%;the error of the front and back of the second layer is 9.89%and 10.8%.For the second simulation,the error of the front and back of the first layer target is 6.0%and 8.0%and the error of the front and back of the second layer target is 10.0%and 10.7%.And for the third experiment,the error of the front and back of the first layer is both 8.0%;the error of the front and back of the second layer is 10.8%and 7.2%,respectively.