Strain Behavior of Concrete Panels Subjected to Different Nose Shapes of Projectile Impact.

Sangkyu Lee,Minjae Son,Hongseop Kim,Jeongsoo Nam,Gyuyong Kim,Gyeongcheol Choe

doi:10.3390/ma11030409

Abstract

This study evaluates the fracture properties and rear-face strain distribution of nonreinforced and hooked steel fiber-reinforced concrete panels penetrated by projectiles of three different nose shapes: sharp, hemispherical, and flat. The sharp projectile nose resulted in a deeper penetration because of the concentration of the impact force. Conversely, the flat projectile nose resulted in shallower penetrations. The penetration based on different projectile nose shapes is directly related to the impact force transmitted to the rear face. Scabbing can be more accurately predicted by the tensile strain on the rear face of concrete due to the projectile nose shape. The tensile strain on the rear face of the concrete was reduced by the hooked steel fiber reinforcement because the hooked steel fiber absorbed some of the impact stress transmitted to the rear face of the concrete. Consequently, the strain behavior on the rear face of concrete according to the projectile nose shape was confirmed.

Highlights

Front-side failure is obtained when a projectile strikes concrete
This study evaluated the influence of projectile nose shape on the strain behavior and fracture
This study evaluated the concrete influence of projectile nose shape on the behavior and fracture properties of fiber-reinforced panels due to projectile impact

Summary

Introduction

Front-side failure is obtained when a projectile strikes concrete At this point, a compressive stress wave is generated and radially transmitted to the rear face of the concrete. A compressive stress wave is generated and radially transmitted to the rear face of the concrete This compressive stress wave is reflected as a tensile stress wave when it reaches the rear face. This action causes a decrease in the magnitude of the compressive wave and an increase in the magnitude of the tensile wave. Cracks and fractures will occur if the generated tensile stress exceeds the dynamic tensile strength of the concrete and the strain limits at any point in the concrete matrix (Figure 1) [1]. Prior research classified the local fracture modes of concrete as penetration, scabbing, and perforation failure [1,2,3,4]

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