Numerical modelling of 3D concrete printing : material models, boundary conditions and failure identification

3D concrete printing (3DCP) attracts significant attention as an innovative manufacturing technology for the construction industry. As one of the challenges in 3DCP, failure mechanisms of 3D printed concrete structures were not well understood yet and hard to predict. The three-dimensional finite element (FE) method is an effective method to simulate such a layer-by-layer process. However, some existing technical issues in FE modelling, including additional initial deformations, failure identification, selection of material models, concrete foundation interactions and initial imperfections, need to be addressed for accurate simulation of 3DCP. In this study, FE models using a novel tracing element approach are developed to capture mechanical behaviours and failure modes of typical 3D printed concrete structures. The developed FE models was validated by comparing the obtained numerical results with those data available in literature. Furthermore, four material constitutive models are investigated analytically and numerically to compare their applicability in modelling 3D printed concrete structures. The obtained results show that the Mohr-Coulomb and Concrete Damage Plasticity (CDP) models can accurately predict failure behaviours of 3D printed concrete structures.