Phase-field modeling of the morphological and thermal evolution of additively manufactured polylactic acid layers and their influence on the effective elastic mechanical properties

This study presents a comprehensive simulation of the fused deposition modeling (FFF) process of polylactic acid (PLA)
using the multiphase-field method. Compared to existing works, this work aims to simulate the overall FFF process. It com-
bines temperature evolution, viscous flow, polymer crystallization, and residual strain calculations within the microstructure
with mechanical property analysis in a single study. Simulation studies were done in the case of the single layer to study the
flowing effect of the filament and the distribution of temperature, viscosity, and relative crystallinity throughout the cooling
process. Afterward, a system of layers with three rows and three columns was investigated. The nozzle temperature, bed
temperature, viscosity, and layer height were varied, and for each case the porosity was calculated. After running mechanical
loading simulations on each case, the effective Young’s modulus was calculated. The simulations show that increasing the
nozzle and bed temperatures leads to a decrease in the porosity, while increasing the layer height increases the distortion in
the pores’ shapes without significantly affecting the porosity. ... mehrThe decrease in porosity leads to an increase in the effective
Young’s modulus of the structure in a linear trend within the investigated porosities. The Young’s modulus–porosity relation
was validated with experimental values from the literature within an average error of 3.6 %