ABSTRACT
Additive Manufacturing (AM) methods like Fused Deposition Modelling (FDM) in 3D printing present the opportunity to construct geometrically complex polymeric reinforcements for cementitious composites. However, FDM 3D printed material can be highly anisotropic such that printing path-dependent models using the Lattice Beam Model (LBM) have been developed. These explicitly model the inter-layer and intra-layer bonds that exist in FDM 3D printed reinforcements by assigning experimentally obtained interface properties that significantly differ from the bulk material. To illustrate the aforementioned methodology, it is used to numerically investigate particularly complex types of FDM 3D printed reinforcement for cementitious composites subjected to bending. These have a Poisson’s ratio that is tailored in accordance with the stress-strain distribution, such that their cross-sections change over the height of the beams. Three Tailored Poisson’s Ratio-reinforcement (TPR) designs are modelled considering printing path-dependent anisotropy as a result of the FDM 3D printing technique. Subsequently, preliminary simulations of these reinforcements submerged in cementitious matrix to form a composite are discussed. The lattice models show that incorporating the anisotropy present in FDM 3D printed reinforcement is important, because simulations assuming isotropic properties result in significant overestimation in strength and completely change the fracture behaviour.
