Investigation of the effects of impactor geometry on impact behavior of reinforced concrete slabs

• Impactor geometry is important parameters affected the behavior of RC members. • Experimental/ numerical studies about impactor geometry are limited in literature. • Three flat-surface and hemispherical hammers with different surface areas are used. One of the important parameters that affect the behavior of the reinforced concrete (RC) members under impact loading is the impactor geometry used for applying impact loading. It is known that changes in the impactor geometry have significant effects on energy transfer to the structural system, deformation distribution, and damage on structural members caused by impact loading. However, there is no encounter with a study with a detailed and comprehensive conclusion on this topic during the literature review. The lack of this kind of conclusion leads to an experimental study with different impactor geometries applying impact loading on RC slabs. These experiments examine the effects of impactor geometry on acceleration-time, displacement–time, impact loading-time, and maximum strain–time behaviors. In addition to those, effects on damage distribution and impact loading behaviors are examined. This study uses three flat-surfaced hammers with different surface areas and a hemispherical hammer. Impact loading is applied at two different magnitudes on specimens. Ls-Dyna software is also used to do numerical analysis for the members. Outputs of the analysis are compared with the experimental results to evaluate the modeling of effects of change in impactor geometry. When the results obtained as a result of the experimental study were examined, it was seen that the change in the geometry of the impactor to which the impact loading was applied significantly changed the behavior of the slabs under the impact loading. The increase in the impactor contact area caused an increase in the impact loading applied to the specimens, and the acceleration, displacement, residual displacement, and strain values measured from the specimens all increased.