Critical impact energy for spalling, tunnelling and penetration of concrete slab impacted with hard projectile

Abstract

Penetration is the basic element of designing protective concrete structure against the local impact damage of hard missile. Impact energy is the dominant cause of damage in moving accidents. When hard projectile collides with concrete target, it is the impact energy of the projectile that makes concrete target to deform. Therefore, it is vital to study critical impact energy required to causes penetration. An analytical model is developed to predict the required critical impact energy for maximum penetration without rear effects in concrete slabs when it is impacted with hard projectile. The nose shape factor Ni also has been introduced with inclusion of empirical friction factor Nf, as modification in Chen & Li nose shape factor for ogive nose hard projectile. The newly developed analytical model and nose shape factor Ni is examined for CRH = 2.0, CRH = 3.0, and CRH = 4.25. It was found that the predicted results from analytical model with nose shape Ni are in close relation with experimental data in all cases as compared to predicted results with traditional Li and Chen nose shape N*. In, General, the analytical model generates encouraging prediction which is consistent and follows a general trend of experimental results.