Hybrid multi-scale modeling of fused deposition modelling printed thermoplastics: An introduction to material degradation parameter

With the increasing popularity of fused deposition modelling (FDM), an improved understanding of the interdependence between process-structure-property (P-S-P) of FDM manufactured (FDMed) parts is imperative. This paper proposes models for linking the microstructure and degradation of properties during the FDM process with the mechanical properties. Through careful and elaborate finite element (FE) modeling, it is demonstrated that there is definite material degradation during the FDM process, which cannot be attributed only to extra voids generated during printing. A novel hybrid multiscale model is proposed to estimate the degradation parameter and utilize this information to predict the printed coupons' properties. Additionally, two methods for generating representative volume element (RVE) are demonstrated using scanning electron microscope (SEM) imaging and density data. For the experimental validation, polyamide (PA) and polylactic acid (PLA) filaments and dogbone samples with multiple raster orientations were tested. The use of degradation parameter during modeling leads to very accurate results for both PLA and PA. Also, it presents insights into the limitations of the FDM process and possible improvements.