<p>Extrusion deposition additive manufacturing (EDAM)
has enabled upscaling the dimensions of the objects that can be additively
manufactured from the desktop scale to the size of a full vehicle. The EDAM
process consists of depositing beads of molten material in a layer-by-layer
manner, thereby giving rise to temperature gradients during part manufacturing.
To investigate the phenomena involved in EDAM, the Composites Additive
Manufacturing Research Instrument (CAMRI) was developed as part of this
project. CAMRI provided unparalleled flexibility for conducting controlled
experiments with carbon fiber reinforced semi-crystalline polymers and served
as a validation platform for the work presented in this dissertation. </p>
<p>Since the EDAM process is
highly non-isothermal, modeling heat transfer in EDAM is of paramount
importance for predicting interlayer bonding and evolution of internal stresses
during part manufacturing. Hence, local heat transfer mechanisms were
characterized and implemented in a framework for EDAM process simulations.
These include local convection conditions, heat losses in material compaction
as well as heat of crystallization or melting. Numerical predictions of the
temperature evolution during the printing process of a part were in great
agreement with experimental measurements by only calibrating the radiation
ambient temperature. </p>
In
the absence of fibers reinforcing the interface between adjacent layers, the
bond developed through the polymer is the primary mechanisms governing the
interlayer fracture properties in printed parts. Hence, a fusion bonding model was
extended to predict the evolution of interlayer fracture properties in EDAM
with semi-crystalline polymer composites. The fusion bonding model was
characterized and implemented in the framework for EDAM process simulation.
Experimental verification of numerical predictions obtained with the fusion
bonding model for interlayer fracture properties is provided. Finally, this
fusion bonding model bridges the gap between processing conditions and
interlayer fracture properties which is extremely valuable for predicting
regions with frail interlayer bond within a part.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/7434068 |
| Date | 16 January 2020 |
| Creators | Eduardo Barocio (5929505) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/FUSION_BONDING_OF_FIBER_REINFORCED_SEMI-CRYSTALLINE_POLYMERS_IN_EXTRUSION_DEPOSITION_ADDITIVE_MANUFACTURING/7434068 |
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