Constitutive model of steel fiber reinforced concrete by coupling the fiber inclining and spacing effect

Abstract

This study aims to establish a new constitutive model considering the fiber spacing and inclining effect for steel fiber reinforced concrete (SFRC) with high fiber content. To consider the influence of the fiber spacing, the fiber group effect factor is proposed for revising the reinforcement effect, and the critical fiber volume fraction is determined as 4.58%. Moreover, the fiber inclined effect factor is established by coupling the snubbing and matrix spalling effect factors, with the optimal inclining angle calculated as 32 degrees. The proposed constitutive model is introduced into Abaqus by the Umat of Fortran code, and the finite element models are established to simulate the tensile and flexural tests of SFRC. The results show that as for the tensile test of SFRC, as the fiber volume increased from zero to 7%, and 10%, the peak stress increased as high as 2.2, and 3.8 times and the strain at the peak point increased 2 and 3.5 times; and under the four-point bending test of SFRC, the toughness index has been greatly improved and reach 36. By comparing with the experimental results, it can be obtained that the proposed constitutive model is feasible for exploring the mechanical property of SFRC.