Challenging the Limits of Fluid FEM Modelling in 3D Concrete Printing

3D Concrete Printing (3DCP) is emerging among additive manufacturing technologies for the construction industry. With 3DCP complex structural components can be built without formwork in a layer-wise fashion, enhancing accuracy, optimizing material use and reducing construction times and waste. However, to fully exploit and control 3DCP it is necessary to develop adequate numerical predictive tools: solid FEM models have been used to predict buildability, while fluid or particle methods are preferred to assess pumpability and extrudability. Currently, a unified numerical framework to simulate the overall 3DCP process is missing. This work intends to take a first step in that direction. A single-phase fluid model of 3DCP based on the Particle Finite Element Method (PFEM) is illustrated. Fresh concrete is modelled with the Bingham law and the static yield stress is increased in time in the layers to reproduce material structuration. In the PFEM framework, a wide range of different phenomena typical of 3DCP can be simulated. In the specific, two 3D printing applications are shown: the virtual printing of a cylindrical object and the prediction of structural failure due to elastic buckling in a rectilinear wall.