Abstract
In the fused filament fabrication (FFF) additive manufacturing process, a part is manufactured by layer-by-layer deposition of thermoplastic filaments extruded from a nozzle. This process results in microscopic voids that are stochastic in size and randomly distributed in space. Also, the elastic properties of the extruded filaments show variation. These uncertainties in the FFF process and the resulting microstructure cause a variation in the structural response (load-displacement curve) of the final printed part. A multiscale uncertainty propagation framework was developed in this study to examine the effect of microscopic inhomogeneity on the variations in the macroscopic structural behavior. Experimental data was used to quantify uncertainty at the micro-scale, while Monte Carlo simulation was used to quantify uncertainty at the meso- and macroscales. A hook model was considered as a case study for uncertainty propagation in the FFF process.