A mesoscale simulation study on the effects of fiber orientation on the fracture behavior of steel fiber reinforced concrete
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The fracture behavior of steel fiber reinforced concrete (SFRC) structures is significantly affected by fiber orientation. To evaluate the optimal fiber orientation patterns in different structures and their effects on fracture evolution, a three-dimensional mesoscale simulation framework was developed in this study. The proposed approach employs a cohesive crack model to describe concrete cracking and incorporates an angle-dependent fiber bond–slip law to capture fiber crack-bridging effects, thereby enabling simulation of multi-crack evolution in SFRC.The complete fracture processes of SFRC with unidirectionally (1D-ASFRC), two-dimensionally (2D-ASFRC), annularly (AASFRC) and full-field (FASFRC) aligned steel fibers are investigated. The results indicate that aligning fibers along the tensile stress directions of different structural components, rather than distributing them randomly, effectively increases the average tensile stress of fibers, thereby enhancing the compressive, flexural, splitting, and impact strengths and toughness of the structures. Finally, SFRC specimens with different fiber distribution patterns were prepared by using a specially designed magnetic field device to control fiber orientation in fresh mixtures. The experimental results confirmed the reliability of the developed models. For structural elements such as beams, columns, slabs, pavements, and perforated plates, the load-bearing capacity can be significantly enhanced by adjusting the fiber orientation according to the structural loading conditions, without increasing the fiber content. The developed mesoscale approach and the magnetic field device can be applied to the design and fabrication of SFRC structures, thereby guiding and promoting their engineering applications.
