Effect of Impactor's Taper Angle on the Response of a Square Slab to a Falling Mass

Abstract

Reinforced concrete (RC) slabs during their service life experience falling mass impacts which are significantly different from quasi-static loading on account of short-term load transference and higher strain rate. Slab being a thin flexural member is prone to short-term dynamic loadings susceptible to irreparable damage or even collapse. Considerable research has been done with round impacting mass, however, the impacting mass needs not necessarily be round and may have a different geometry such as a rolling boulder or fragmented rock mass. To simulate the practical impacting geometries of the falling mass, eight different variations of the geometries varying from flat of 300mm diameter followed by 40mm flat with tapering from 90° to 0° in increments of 15° keeping the material characteristics and drop height of the falling mass constant across all the eight cases, have been considered herein to investigate the influence of impactor’s taper angle on the anti-impact response of the validated square slab in Abaqus Explicit package program. A comparison of several response parameters including displacement, damage, stress distribution, and plastic dissipation energy has been done with the validated model, and the geometries of the impactor causing the maximum and minimum damages are identified. A key finding from this study is that all considered impacting geometries lead to bond failure in the lower layer of the re-bars, however, the impactors having the geometry with taper angles below 45° possess the capacity to induce bond failure in the re-bars of the upper layer too, beyond the impacted region.