3DLightBeam+. Design, simulation, and testing of carbon-efficient reinforced 3D concrete printed beams

The paper presents a workflow for the design, material testing and numerical simulation of shape-optimised reinforced 3D Concrete Printed (3DCP) beams tested structurally in three-point bending. Building upon previous research on structurally optimised toolpath planning for 3DCP, the presented work suggests a method for the computational design optimisation process based on material efficiency principles and the parallel development of a lossless data transfer tool from the 3D modelling environment to a Finite Element Analysis (FEA) workspace taking into account the layered process characteristic of 3DCP and the consequent weak interactions generated between adjacent printed concrete filaments. The proposed FEA model was calibrated through cored cylindrical specimens and then applied to the design, fabrication and experimental testing of a proof-of-concept shape- and infill-optimised 3-metre simply supported beam. The comparative analysis of simulation and structural testing proves the reliability of the numerical model, which correctly estimated peak load and damage patterns for 3DCP. The tests highlight how, with a shear failure mode, the dominant cracks start from the support region and reach the area of load application. The presented work advances the research in 3DCP by developing 3DLightBeam+, a carbon-efficient reinforced concrete beam design with a 200% higher flexural strength-to-weight ratio than a full comparable beam. The beam is conceived through a seamless workflow for its FE analysis and structural verification that accurately predicts structural capacity and behaviour without destructive testing methods.