The Study Of Numerical Simulation Of High-speed Penetration Into Reinforced Concrete

The present paper studied the problem of the numerical simulation of high-speedpenetration into reinforced concrete target. By the theoretical analysis and numericalsimulation methods, this paper has carried on the analysis and research systematically ofkinetic energy projectile penetrating into reinforced concrete plate and double-layer liner aswell as standoff distance influencing on shaped charge jet penetration. Based on the reviewof the research achievements on penetration of reinforced concrete target, the current paperfocuses on some of the problems. The specific works are given as follows:1. Using LS-DYNA finite element software, the numerical model of kinetic energyprojectile penetrating into reinforced concrete plate was established by separate modelingmethod. The residual velocity and the acceleration curve of projectile, as well as destructionof the target plate, were studied according to predecessor’s test. The effect of target positionon penetration was also analyzed in comparison. Numerical calculation results wereconsistent with the experimental results, and the results showed that the rebar had anobvious decelerate effect on projectile, improving the target plate’s resistance to penetrationwell.2. For the jet formed by small cone angle shaped charge, it has a large velocitygradient. Based on the virtual origin concept, the tensile deformation of jet in movementwas analyzed, and the jet’s axial and lateral size change regular was obtained. On the basisof the hydrodynamics penetration theory, variations of the cavity radius in the penetratingprocess were analyzed and predicted, and a theoretical model to predict the cavity radiusversus penetration depth was developed. Using the finite element software AUTODYN, thenumerical model of jet penetrating into concrete target was set up for validation, and thenumerical results coincided with the theoretical derivation.3. The effect of standoff distance on shaped jet penetration was researched withnumerical simulation method. Using verified numerical model above, the changes of jetpenetration depth and hole diameter in different standoff distance were analyzed. For thestructure of the shaped charge with cone angle60°, the best standoff distance was1.5-2times of charge diameter, and this result had a good agreement with the experimental resultsof other researchers.4. The effect of different material combination types of double-layer liner on shapedjet penetration was researched. The overwhelmed model of double-layer liner in jetformation and the influence of materials’ acoustic impedance on the propagation of the shock waves in different materials were discussed. Compared the single copper jet’scharacteristics with the aluminum-copper double jet, the conclusion was got thatdouble-layer liner structure could improve the shaped jet’s performance. Changing thematerial combination type of double-layer liner, the velocity, diameter, length of jet andpenetration depth, hole diameter of target board could be obtained and compared, which hasa relationship with materials properties such as acoustic impedance and density. The resultsshowed that the jet formed by double-layer liner had a significantly greater speed than thesingle-layer liner, and the greater acoustic impedance ratio of inner and outer layer material,the greater the penetration depth of concrete target plate. If heavy metal was the outer layerin the double-layer liner structure, the formed jet could also have a bigger diameter.