Impact behavior of lightweight fiber-reinforced sandwich composites

The results of an experimental study on the impact behavior of sandwich composite panels, in-filled with lightweight fiber-reinforced concrete between steel faceplates, are presented. In this study, the panels were impacted by a 58-kg drop-weight projectile with a hemispherical head from a height of 4.0 m. Parametric studies in these tests include concrete type and volume percent of fiber in the concrete core. From the tests, the impact force and indentation in the top steel plate were measured while visual damage in the core material was noted. The experimental results indicated that the plain concrete cores without any fiber reinforcement cracked into separate pieces upon impact. On the other hand, the concrete cores incorporating 1 to 2% fiber content remained intact after impact, with increasing reduction in the average crack width as well as number of crack formations as fiber content increased. In addition, the concrete core incorporating 2% fiber had no radial cracks, which are cracks propagated outwardly from point of impact, except for local indentation. Depth of local indentation was observed to decrease with the increase in core strength. From the impact shear test on lightweight concrete, it is clear that hooked-ends steel fiber performed better under impact.