Fast Thermomechanical Predictions of the FFF Process for High-Performance Semi-Crystalline Thermoplastic Composites

Conference Abstract: Fused Filament Fabrication (FFF) has emerged as a versatile and cost-effective additive manufacturing process for producing parts with high-performance semi-crystalline thermoplastic composites. Numerical simulations of the thermomechanical behavior of a part during printing facilitate the design process as the warpage and mechanical properties can be predicted without doing any actual printing. In this context, we present a finite element analysis (FEA) toolchain tailored to the numerical simulation of the FFF process for semi-crystalline thermoplastic composites.
As fidelity to the actual printing process is of paramount importance, our workflow directly uses the 3D printer toolpath instructions in G-code format to construct a voxelized mesh representative of the printed part for FEA simulations. This automated preprocessing step significantly decreases the modeling time and yields a mesh that is geometrically-accurate and all the necessary information for the numerical simulations, such-as time-stepping data and extruder, build plate and chamber temperature settings. Using this data, our in-house, high-performance, parallel FEA solver is then tasked to solve the thermomechanical equations during the simulated build process, thereby giving access to crucial time-dependent quantities, including temperature, crystallinity, stress, strain and deformations. An element activation scheme that dynamically adds new elements to the mesh is used to represent the deposition of new material and reduce the computational cost.
By predicting efficiently and accurately the transient temperature distribution and residual stresses during the printing process, our workflow provides valuable insights into the FFF process. These insights are critical to better understand the FFF process, optimize the processing parameters, improve the quality and mechanical properties, and meet the stringent requirements of the automotive and aerospace industries for parts made with high-performance semi-crystalline thermoplastic composites. Our approach will be demonstrated on an industrial part for which the prediction of the temperature distribution and deformations will be compared to experimental measurements.