Material modelling of FDM printed PLA part

Abstract

This paper focuses on modelling inelasticity of additively manufactured polylactide (PLA) thermoplastic using Fused Deposition Modelling (FDM) printing technology. The material response of PLA is viscoplastic and temperature-dependent, as is typically seen for thermoplastics. The inelastic deformation of printed PLA undergoes initial yielding, strain softening, and subsequent failure. The Three-Network (TN) constitutive model was employed in this work, which captures experimentally observed material response and consists of three molecular equilibrium and time-dependent viscous networks that act in parallel. The parameter identification was performed in accordance with experimental data from uniaxial testing and a validation experiment was carried out by loading plate with a hole and measuring its strain distribution using Digital Image Correlation (DIC) method, which was compared with the predictions from Finite Element Analysis (FEA).