Penetration depth in concrete for nondeformable missiles

The ability of the NDRC equations to estimate the penetration depth in concrete structures has been reevaluated using the presently available test results. This study confirms the industry notion that the NDRC equations overpredict the penetration depth. The NDRC equations, when used with a safety factor, can give a penetration depth about two standard deviations away from the mean value. In a probabilistic formulation the use of this penetration depth is over-conservative and unrealistic. The NDRC equation is updated here statistically using the presently available test results. This statistical NDRC equation significantly improves the predicted penetration depth. However, the form of the NDRC equation may not be ideal. A new relationship is proposed here to estimate the penetration depth by introducing a dimensionless impact factor. It has been shown here that the proposed relationship is better than the NDRC or even the statistical NDRC equations.