Finite element composite simplification modeling and design of the material extrusion wave infill for thin-walled structures

The finite element composite simplification model (CSM) for modelling the material extrusion (MEX) wave infill of a thin-walled structure (TWS) with generalized geometries and loading conditions is presented. The MEX wave infill is a sine wave infill pattern used to generate a lightweight TWS with desired bending properties. In CSM, the wave infill and TWS faces are modelled as a homogenous stacked composite, which significantly reduces the computation and setup time associated with full-scale finite element modeling. Analytical models are presented to determine the effective material properties of the homogeneous core of the CSM. Previously reported four-point flexural experiments were used to validate the CSM. CSM has been shown to predict the experimentally measured four-point bending stiffness within 15%. Using CSM, fixed flat- and curved-plate cantilevers with uniform and varying wave infill are analyzed. These analyses show CSM to be a good finite element tool for modeling complex geometries with wave infill for TWSs.