Cavity expansion model and penetration mechanism of concrete with different strengths based on the Ottosen yield condition

Aiming at the urgent demand for theoretical research and engineering application of deep super hard targets in the field of damage and protection, the response zone and boundary conditions during the cavity expansding process are optimized in this paper based on the improved Ottosen yield condition. The entire process of cavity expansion is solved, the changes in the response zone of concrete with different strengths are analyzed. According to the relationship between cavity boundary stress and cavity expansion velocity, a calculation model of projectile penetration depth is established, and the penetration depth of projectile penetration into concrete with different strengths are calculated. The mechanism of the influence of target strength on penetration depth is also analyzed. The results show that the elastic and plastic cracking zone of high-strength concrete is larger and the compacted zone is smaller, indicating that high-strength concrete is more brittle and compact. And the addition of plastic cracking zone can better reflect the phenomenon of concrete with different strengths in penetration. By comparing with the experimental data, it can be seen that the cavity expansion theory established in this paper has good applicability for normal concrete and high-strength concrete. The relationship between radial stress and cavity boundary velocity and the penetration depth also can be accurately calculated by this theory. With the increase of concrete strength, the difference in the cavity boundary stress of the concrete becomes smaller, resulting in a smaller increase in the penetration depth of the projectile as the velocity increases, and the penetration depth of the projectile decreases and gradually tends to a certain value at the same speed. © 2023 Explosion and Shock Waves. All rights reserved.