A Particle Finite Element Method for investigating the influence of material and process parameters in 3D Concrete Printing

3D Concrete Printing (3DCP) is an innovative construction technology that enables the efficient fabrication of complex objects through the extrusion of cementitious materials. However, the quality and integrity of the structural components are critically dependent on the accuracy of the extrusion and layer deposition processes. This study employs the Particle Finite Element Method (PFEM), consisting of an updated Lagrangian FEM formulation equipped with an efficient remeshing scheme, to virtually reproduce 3D printing of cementitious materials. PFEM allows for automatically tracking the free-surface and efficiently modelling the material as a non-Newtonian Bingham fluid. The numerical framework is applied to assess the impact of key material and process parameters (including yield stress, viscosity, nozzle diameter, nozzle height, translational velocity, and extrusion velocity) on the morphology of the printed layers. Results allow to create a prototype design chart providing an estimate of the filament shape based on selected material and printing parameters in free-flow deposition 3DCP. Additionally, from simulations, a dimensionless map can be generated distinguishing between five printing regimes: quasi-Newtonian flows, free-flow deposition of round shapes, free-flow deposition of spread shapes, filament tearing, and layer-pressing.