Time-dependent mechanical properties in polyetherimide 3D-Printed parts are dictated by isotropic performance being accurately predicted by the generalized time hardening model
Author
García Granada, Andrés-Amador
Reyes Pozo, Guillermo
Gómez Gras, Giovanni
Puigoriol Forcada, Josep Maria
Salazar Martín, A.G.
Other authors
Universitat Ramon Llull. IQS
Publication date
2020-03Abstract
The Fused-Deposition Modelling (FDM) technique has transformed the manufacturing discipline by simplifying operational processes and costs associated with conventional technologies, with polymeric materials being indispensable for the development of this technology. A lack of quantification of viscoelastic/plastic behavior has been noted when addressing FDM parts with Polyetherimide (PEI), which is currently being investigated as a potential material to produce functional end-products for the aerospace and health industry. Primary and secondary creep along with stress relaxation tests have been conducted on FDM PEI specimens by applying stresses from 10 to 40 MPa for 100 to 1000 min. Specimens were 3D printed by varying the part build orientation, namely XY, YZ, and XZ. Creep results were fitted to the Generalized Time Hardening equation (GTH), and then this model was used to predict stress relaxation behavior. FDM PEI parts presented an isotropic creep and stress relaxation performance. The GTH model was proven to have a significant capacity to fit viscoelastic/plastic performances for each single build orientation (r > 0.907, p < 0.001), as well as a tight prediction of the stress relaxation behavior (r > 0.998, p < 0.001). Averaged-orientation coefficients for GTH were also closely correlated with experimental creep data (r > 0.958, p < 0.001) and relaxation results data (r > 0.999, p < 0.001). FDM PEI parts showed an isotropic time-dependent behavior, which contrasts with previous publications arguing the significant effect of part build orientation on the mechanical properties of FDM parts. These findings are strengthened by the high correlation obtained between the experimental data and the averaged-coefficient GTH model, which has been proven to be a reliable tool to predict time-dependent performance in FDM parts.
Document Type
Article
Published version
Language
English
Subject (CDU)
54 - Chemistry. Crystallography. Mineralogy
62 - Engineering. Technology in general
Keywords
Control de processos químics
Termoplàstics--Propietats mecàniques
Creep
Stress relaxation
Fused deposition modelling
Polyetherimide
Process parameters
Mathematical characterization
Generalized time hardening model
Pages
16 p.
Publisher
MDPI
Is part of
Molecules. Vol.12, n.3 (2020), 678
This item appears in the following Collection(s)
Rights
© L'autor/a
Except where otherwise noted, this item's license is described as http://creativecommons.org/licenses/by/4.0/