No abstract

Axisymmetric and three-dimensional smoothed particle hydrodynamics (SPH) models are developed to simulate normal and oblique perforation of 12 mm-thick Weldox 460 E steel plates. In the models, a particle-to-particle contact algorithm including friction effect is employed to model interactions between projectile and target plate. A constitutive model coupling viscoplasticity and ductile damage is implemented to describe material behaviors of target plate. Both axisymmetric and three-dimensional SPH models are validated by existing experimental results. By using axisymmetric models, effects of projectile structure on normal perforation are systematically studied. Two factors of projectile structure, nose shape and aspect ratio, are considered. Residual velocities, ballistic limits and failure modes are obtained for different projectile nose shapes and aspect ratios. Effects of nose shape and aspect ratio on ballistic limits predicted by SPH simulations are compared with those obtained by an analytical equation. By using three-dimensional models, oblique perforation is simulated. Effects of oblique angle on impact processes are analyzed. Intervals of critical oblique angle of ricochet are obtained for different impact velocities and caliber-radius-head values of ogival projectile. The results obtained in this work can provide reference for the design of protective structures with steels and similar materials. The SPH with contact algorithm including friction effect is proved to be a very effective method for ballistic impact simulation.

For smoothed particle hydrodynamics (SPH), homogeneous particle distribution is important to ensure the computational accuracy and stability, but it is hard to achieve this for complex geometries. In this paper, a new particle generation method is developed to generate particles for arbitrary 2D geometries. In the method, the geometry required for generating particles is orthogonally partitioned into a series of sub-domains. Among the resultant sub-domains, the most ones having standard area are directly converted into particles. The others are iteratively meshed into elements with nearly standard area and particles are placed according to these elements. The present method is implemented based on Abaqus. Examples of particle generation are given to compare various particle generation methods. It is found that the present method shows advantages over some existing methods in the approximation of geometric boundary as well as the regularity and homogeneity of particle distribution. Several physical problems are adopted to examine the influence of initial particle distribution on SPH solution. The calculated results show that particle distributions generated by the present method can lead to better accuracy and stability than those created by some existing methods.

Purpose Metal plates are usually used as protective shields of engineering structures, which probably undergo multiple projectile impacts resulting from gunshot and blast. Though a large number of studies have been conducted on the performance of metal plates under a single projectile impact, few studies have explored their performance under multiple projectile impacts. This paper aims to explore the performance of Weldox 460 E steel plates against multiple projectile impacts through numerical simulation. Design/methodology/approach A three-dimensional coupled finite element (FE) and smoothed particle hydrodynamics (SPH) model was developed to simulate the perforation of a 12-mm-thick Weldox 460 E steel plate by an ogival projectile. The model was verified by existing experimental data. Then, it was extended to investigate the same target plate subjected to impacts with multiple projectiles. Simultaneous impacts with different number of projectiles, as well as sequential impacts with two projectiles, were considered. Findings Effects of spacing between projectiles on residual velocity of projectile, ballistic limit and failure mode of target were revealed for simultaneous impacts. Effects of spacing and axial distance between projectiles on residual velocity of projectile were explored for sequential impacts. Originality/value This work developed an advanced FE–SPH model to simulate perforation of steel plates by multiple projectiles, and revealed the effects of multiple impacts on ballistic performance of steel plates. It provides guidance for the design of protective structures/shields in various engineering applications.