Coupled FEM-SPH simulation of the protective properties for metal/ceramic composite armor

To support the structural optimization design of metal-ceramic armor against penetration protection performance, this paper optimizes the armor in terms of protection material, armor structure, and bullet resistance mechanism, and envisages a new metal-constrained ceramic composite armor, which overcomes the disadvantages of ceramic material fragility. A coupled finite element-smooth particle hydrodynamics (FEM-SPH) algorithm is used to simulate the penetration process, and the influence of ceramic unit shape and size on the armor protection performance is investigated by quantitatively comparing the bullet energy loss, velocity change, penetration depth, and other indicators that reflect the ballistic protection mechanism. The results show that metal-confined ceramic armor has repairable performance, and filling ceramic units can reduce armor failure area, save armor repair time, and extend armor service life. When the velocity of the projectile is less than 500 m/s, the damaged area of the armor filled with small-sized unit ceramics (1/4 bullet caliber) is small and easy to repair; when the velocity of the projectile is greater than 500 m/s, the armor filled with large-sized unit ceramics (2 times the bullet caliber) can effectively increase the bullet residence time and improve the armor's resistance to elasticity. The results of this paper can provide a reference for the optimal design of the armor structure.