Mechanical characterisation for numerical simulation of extrusion-based 3D concrete printing

• Published in: Journal of Building Engineering Vol. 44; p. 102944
• Main Authors: van den Heever, Marchant, Bester, Frederick, Kruger, Jacques, van Zijl, Gideon
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-12-2021
• Subjects: 3D concrete printing; Experimental mechanics; Finite element analysis; Mechanical characterisation; Numerical simulation; Experimental mechanics; Numerical simulation; 3D concrete printing; Finite element analysis; Mechanical characterisation
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2021.102944

Extrusion-based 3DCP is experiencing exponential advancement in process, control, material, and fresh-state analysis technologies, strategically poising 3DCP to become an industrial manufacturing process for infrastructure development. To elucidate the mechanical characterisation and numerical simulation of 3DCP elements synergy among experimental and computational mechanics is required. Such activities should characterise the unique material properties of printed components to permit limit state design procedures and the correct prescription of finite element (FE) model parameters. In this research, mechanical characterisation procedures that experimentally evaluate the anisotropic material characteristics of a fibre-reinforced printable concrete (FRPC) are presented. These procedures are comprised of direct tensile, uniaxial compression, Young's modulus, and four-point bending (FPB) crack mouth opening displacement (CMOD) tests. The results portrayed anisotropic non-linear and similar elastic behaviour (in terms of Young's modulus) in all experimental tests conducted. From the mechanical characterisation tests two elastic parameters, seven strength parameters and five inelastic parameters are ascertained. The experimental findings relating to the material characteristic parameters are validated via supplementary numerical evaluation, and suitable constitutive relations are selected. The mechanical parameters are implemented in an anisotropic Rankine-Hill continuum multi-surface plasticity FE model, and the FPB-CMOD fracture response of 3DCP specimens is simulate with respectable agreement.
•The linear and non-linear mechanical characteristics of FRPC are experimentally evaluated.•The degree of anisotropy is determined, and suitable constitutive relations are selected.•A robust anisotropic continuum FE model adaptable to 3DCP is presented.•The employed layer pressing strategy exhibits potential for interlayer fibre breaching.•A non-rectilinear pressed interface between adjacent filaments improves tensile capacity.