PENETRATION OF CONCRETE TARGETS USING A MODIFIED HOLMQUIST-JOHNSON-COOK MATERIAL MODEL

For concrete target penetration and/or perforation simulation, the Holmquist-Johnson-Cook (HJC) material model is widely used as concrete material model. However, the strain rate expression of the model has failed to explain the sudden increase in concrete strength at high strain rates. The pressure-volume relationship of the HJC model is complex and requires a large number of material constants. In this study, a modified Holmquist-Johnson-Cook (HJC) model is proposed for concrete material under high velocity impact. The modification involves simplification and improvement of the strain rate expression and pressure-volume relationship. Material parameters identification procedure for the MHJC model is also elaborated. The numerical simulations using the proposed model show a good agreement with experimental observations, especially, on the residual velocities, penetration depths and failure patterns of the target plates. These validate the applicability of the MHJC model for high velocity projectile impact studies for concrete.