Dynamic finite cylindrical cavity-expansion models for cellular steel tube confined concrete targets normally impacted by rigid sharp-nosed projectiles

Cellular steel-tube-confined concrete (CSTCC) targets show improved anti-penetration performance over single-cell STCC targets due to the confinement effect of surrounding cells on the impacted cell. Dynamic finite cylindrical cavity-expansion (FCCE) models including radial confinement effect were developed to predict the depth of penetration (DOP) for CSTCC targets normally penetrated by rigid sharp-nosed projectiles, and stiffness of radial confinement was achieved with the elastic solution of infinite cylindrical shell in Winkler medium. Steady responses of dynamic FCCE models were obtained on the assumption of incompressibility of concrete, failure of comminuted zone with Heok-Brown criterion and two possible response modes of the confined concrete in the impacted cell. Furthermore, a DOP model for CSTCC targets normally impacted by rigid projectiles was also proposed on the basis of the dynamic FCCE approximate model. Lastly, relevant penetration tests of CSTCC targets normally penetrated by 12.7 mm armor piecing projectile (APP) were taken as examples to validate the dynamic FCCE models and the corresponding DOP model. The results show that the DOP results based on dynamic FCCE model agree well with those of the CSTCC targets normally penetrated by rigid conical or other sharp-nosed projectiles.