Thickness optimisation in 3D printed concrete structures

Abstract

Layer pressing in 3D concrete printing (3DCP) allows to continuously modify the thickness of printed laces by changing adequately the robot speed. However, most applications consider a constant thickness throughout the printing and do not leverage all the possibilities from robotic technologies. The aim of this paper is to demonstrate the potential offered by thickness variation to achieve higher structural efficiency and to lower the material usage. To do so, analytical solutions for stress and buckling of tapered heavy column are recalled and highlight a potential of reduction of 25% of material for simple geometries with materials with low structuration rate. Numerical optimisation based on a penalty method and on the finite element simulation with shell elements is then implemented to minimise the volume of printed components for more complex geometries. Promising results are observed and should encourage the 3DCP community to further study this previously unexplored dimension of the process.