Analysis Of Dynamic Response Of Large-volume Concrete Under Projectile Penetration And Explosion

In modern warfare,high-precision and high-power ground-drilling weapons have become the core technical means on the informationized battlefield.Public data shows that existing ground-drilling weapons can effectively strike targets in deep underground structures and have a super-damaging effect on media such as concrete and rocks.The rapid development of these high-performance weapons,especially precision-guided deep earth-penetrating weapons,poses a serious threat to national defense engineering and other engineering structures with an important strategic position.Studying the penetration and damage of earth-penetrating weapons on concrete structures has become engineering protection Hot issues that departments need to solve urgently.In this paper,the method of combining experimental research and numerical simulation was used to test the damage of the concrete medium by the high-speed projectile penetrating the concrete target and the internal explosion of the charge,mainly including the following points:(1)The experiment of projectile penetrating the concrete target at different speeds was carried out to study the variation of penetration depth and projectile mass loss with projectile velocity.At the same time,the finite element software AUTODYN is used to perform numerical simulation on the penetration test.Combined with the widely used empirical formula of penetration depth,the penetration depth of the projectile is compared and checked.According to the numerical simulation results,the relationship expression between penetration depth and velocity of the high-speed projectile is fitted.(2)Based on the current research on the concrete RHT model,numerical simulation experiments were conducted on the participating failure strength coefficient,fracture energy,damage coefficient and minimum failure strength value in the RHT model.The influence rule of the damage effect under the internal explosion,and the material parameters of the RHT model suitable for the research work in this paper are proposed.(3)Adopt the method of unfilled charge with reserved charge hole,design a numerical simulation of 10 kg charge TNT explosive explosion inside concrete,and study the internal explosion process of concrete medium.A field test of equal dose was designed to verify the reliability of the numerical simulation results,and the attenuation law of shock wave propagation,the crater effect of large length-to-diameter ratio explosive explosion,the distribution of explosive overpressure and the driving ability of the shock wave to the target were obtained.The results show that with the increase of the projectile velocity,the penetration depth increases first and then decreases.For the 60Si2 Mn projectile,there is a limit penetration depth and a corresponding limit penetration velocity.By fitting the penetration depth obtained at different penetration speeds,an engineering calculation formula that can be used to predict the penetration depth of high-speed projectiles is obtained.For the explosion of the internal charge of the large-volume concrete,the overall structure of the concrete target body is destroyed,resulting in large gaps,many penetrating cracks,and a large number of concrete blocks scattered at the same time,only a large block of concrete exists at four corners.The numerical simulation results show that the non-positive reflections produced by the inclined surface of the concrete have a significantly lower cancellation effect on the forward wave than the vertical surface.