5.3 Effect of projectile mass on the simulated penetration

The effect of the projectile mass on the penetration was assessed by considering three different masses in the simulation – 0.2, 0.4, and 0.6 kg, respectively. Other properties of the projectiles were kept the same. The simulation data are presented in Figure 14. From the figure it can be noticed that the projectile penetration depth increases as its mass increases (a) whereas the penetration speed decreases at smaller rates for larger mass projectiles (b).

In the figure above, the concrete slab perforation process at selected time steps was initiated at a striking velocity of 500 m/s. Different steps correspond to different times, which can be obtained from the simulation history record. As shown, widespread cracking, progressive gross failure, and fragmentation during

Penetration of projectile into concrete target was investigated in this research by

using both experimental methods and numerical simulations. A lab test system which is able to launch steel projectile into cement concrete targets was successfully built. Projectile package driven by propellant gas enables a steel projectile to penetrate into cement concrete targets at different speeds. Finite Element Method (FEM) was utilized to simulate the penetration process of projectile into a concrete target. A projectile is considered as rigid material with no deformation during the penetration process. Cement concrete targets can be modeled using a concrete damaged plasticity model. Several major effects are estimated by FEM simulation including diameter, mass and initial speed of the projectile. Additionally, numerical simulation using Discrete Element Method (DEM) was employed to simulate the penetration process of projectile into cement concrete target. A calibration method was developed to obtain microscopic parameters from macroscopic parameters of concrete. Penetration process can be modeled using the time history of the depth, initial velocity and deceleration of the projectile then compare results with empiri-

cal predictions results of previously conducted simulations.

Virginia Tech Transportation Institute, Blacksburg, USA

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: cdruta1@vt.edu

provided the original work is properly cited.

penetration can be visualized.

Concrete Microstructure Characterization and Performance

DOI: http://dx.doi.org/10.5772/intechopen.90500

6. Conclusions

Author details

Cristian Druta

45

Figure 14.

Penetration depth and speed reduction of projectiles with different masses. (a) projectile penetration depth increases as its mass increases whereas (b) the penetration speed decreases at smaller rates for larger mass projectiles.

### 5.4 Visualization of DEM simulation

After creating the target and projectile models, it is convenient to assign different striking velocities to the projectile and perform penetration simulation. Through PFC3D coding, the entire penetration process can be simulated at selected time steps (Figure 15).

Figure 15. Visualization of the penetration process using DEM (Zhou et al., 2009).

In the figure above, the concrete slab perforation process at selected time steps was initiated at a striking velocity of 500 m/s. Different steps correspond to different times, which can be obtained from the simulation history record. As shown, widespread cracking, progressive gross failure, and fragmentation during penetration can be visualized.
