3D numerical modeling of projectile penetration into rock-rubble overlays accounting for random distribution of rock-rubble

• A 3D model of grouted concrete rock-rubble overlay was developed firstly.
• The randomness of rock-rubble in distribution and shape is taken into account.
• The stopping and deflecting mechanism of target can be studied realistically.
• Configurations of target affect penetration depth and trajectory greatly.
• Impact obliquity affects penetration depth and yawing angle significantly.

This paper presented a three-dimensional (3D) finite element analysis approach to study the projectile penetration into rock-rubble overlays considering the randomness of rock-rubble in shape and distribution. The generation algorithm of 3D rock-rubble with random size and shape was firstly proposed. The dropping and compacting algorithms for the random distribution of all particles of rock-rubble in an overlay were then developed. Thirdly, a finite element grid was formed using the mapping algorithm. An analysis approach for the 3D finite element model of the random distribution of all particles of rock-rubble in an overlay was established by employing the hydrocode LS-DYNA taking into account the different materials properties and contact effect. In order to validate the analysis approach, the numerical results were compared with the limited test data, and a good agreement was obtained. Finally, numerical studies of the projectile penetration into the grouted concrete rock-rubble overlays were presented under different impact conditions, focusing on the penetration depth, yawing angle, trajectory and projectile deformation. It is indicated that impact obliquity affects the penetration depth, terminal yawing angle and penetrator deformation greatly. In order to reveal the stopping and deflecting mechanism of rock-rubble overlays, parametric studies were carried out to analyze the effects of different impact conditions and target configurations on projectile penetration. The numerical results show that the size, strength and volume percentage of rock-rubble and grouted concrete strength are critical to penetration depth and terminal yawing angle.

Figure optionsDownload high-quality image (332 K)Download as PowerPoint slide