Process-informed simulation of Big-Area Additive Manufacturing (BAAM) of polymers

Abstract

Process-induced deviation from the intended geometry is a challenge in additive manufacturing, particularly with increasing part size. To address this problem, a modeling workflow was created for polymer-extrusion Big Area Additive Manufacturing (BAAM) using sequentially-coupled thermal and mechanical finite element simulations with focus on stress state and component deformation. Thermal simulations oriented and placed material via an Abaqus/Standard user subroutine and accounted for conductive, convective, and radiative heat transfer to calculate thermal evolution. Mechanical simulations utilized the calculated thermal evolution to calculate thermally-induced stresses and deformations. Simulations were validated via experimental thermal and geometric data from a 3319.1 mm × 235.0 mm × 1016.0 mm corrugated wall printed from carbon fiber reinforced PETg (cfrPETg). Simulated and experimental temperatures were within $\pm 10$  K; simulated and experimental deformations of the lower surface were within 5% (i.e. 2.74 and 2.62 mm, respectively) after accounting for a 0.20-mm ridge attributable to an experimental build plate discontinuity. Lastly, a first-order sensitivity analysis examined the influence of different material properties on warpage and residual stress. For the factors and levels considered, coefficient of thermal expansion (CTE) had the greatest influence on warpage, thus identifying the characterization and tailoring of CTEs as important research topics.