Modelling of 3D-printed bio-inspired Bouligand cementitious structures reinforced with steel fibres

Latencies and limitations exist in the simulation of bio-inspired structures or highly complex geometries manufactured by digital concrete fabrication. This study develops a computational framework to portray the anisotropic material attributes and predict the crack patterns of hardened 3D printed fiber-reinforced concrete beams. Bio-inspired Bouligand structures printed with four pitch angles of 0˚, 15˚, 30˚, and 45˚ are adopted to validate the numerical model. Extensive experiments, including uniaxial compressive tests, splitting tensile tests, and three-point bending tests, are conducted. The material model is attained from the samples extracted from the printed concrete blocks with and without steel fibres after a 28-day curing age for an accurate representation of the design and process. The micromechanical modelling approach is employed to obtain the homogeneous materials for the macro-scale model. The finite element (FE) analysis provides sound agreement with the experiment results of both stress–strain curves and crack patterns. In addition, under bending loading, the 3D printed beams with a unidirectional printing pattern or a small pitch angle perform better than those with larger pitch angles.