Numerical Investigation of Fibers Effects in SFRC under Dynamic Tension

This study investigates the effects of fibers in steel fiber reinforced concrete (SFRC) on its mechanical properties and failure processes under different loading rates using LS-DYNA. A single fiber pullout test is simulated first to validate the material models and parameters used in the numerical simulations. After the validation, SFRC specimen with a single steel fiber under uniaxial tension is modelled at the mesoscale to present the failure process and the crack development in the specimen. The effects of fibers and the strain rate on the strength, stiffness and toughness of the SFRC are analyzed based on the stress-strain curves. Then SFRC specimens with multiple steel fibers are modelled. The effects of the fiber content on the dynamic properties of the SFRC specimen, such as the dynamic increase factor of its tensile resistance, are evaluated. The simulation results show that the mechanical properties of SFRC can be influenced by both the steel fiber content and the loading rate. The incorporation of steel fibers can lead to an increase of the maximum tensile resistance, the corresponding yield displacement as well as the fracture energy of the SFRC specimens; however the rate-sensitivity is less significant at higher fiber volume content.