Title: Multi-scale Material Modeling and Print Simulation for “First Time Right” Additive Manufacturing

Authors: Olivier Lietaer, Sylvain Bouillon, Elodie Seignobos, and Lucie Berger

DOI: 10.33599/nasampe/s.19.1519

Abstract: Additive Manufacturing of polymers is transitioning from rapid prototyping to a true industrial production technique. While it brings valuable opportunities to the industry, such as drastically decreasing the time-to-market of new products or enabling lightweight, multi-material and multi-functional designs, it also comes with a series of challenges for the engineers. The reliability of the mechanical properties of the final part still has some uncertainty and is not fully supported by standard engineering tools. Dimensional accuracy is not always met and cannot be predicted prior to printing. To cope with these issues, the engineering workflow which is daily applied for traditional manufacturing processes needs to be replicated and adapted to the Additive Manufacturing. Specifically, Additive Manufacturing of polymers and composites shows a very strong influence of the manufacturing on the material and global component behavior and its modeling constitutes a true multi-scale challenge. In this paper, insights on how the process simulation of FDM/FFF or SLS method can be solved via coupled thermo-mechanical models are presented. The numerical simulation follows the real printing workflow, takes into account the process setup and the material behavior, allows to predict the deformed shape of the part and residual stresses and offers warpage compensation techniques. An industrial application of process simulation is shown to demonstrate the validity of warpage predictions. Finally, a strongly coupled process-structure methodology is presented that predicts the as-printed mechanical behavior. This approach links the material anisotropy and the process-induced microstructure to the as-printed part performance. The part strength sensitivity to the build direction is also highlighted. This integrative workflow, which accounts for the full manufacturing history of the part, enables the design validation and the optimization of the performance of AM designs, as demonstrated on an automotive engine air manifold.

References: 1. Digimat Users' Manual Release 2018.1, e-Xstream engineering (2018). 2. Eshelby, J. “The determination of the elastic field of an ellipsoidal inclusion and related problems”. Proceedings of the Royal Society of London, 1957. pp. 376–396. 3. Doghri, I., Ouaar, A. “Homogenization of two-phase elasto-plastic composite materials and structures: study of tangent operators, cyclic plasticity and numerical algorithms”. Int. J. Solids Struct. 40 (2003): 1681-1712.

Conference: SAMPE 2019 - Charlotte, NC

Publication Date: 2019/05/20

SKU: TP19--1519

Pages: 8

Price: FREE