Mesostructure design and analysis of additive manufactured polymers
Abstract/Contents
- Abstract
- Additive manufacturing (AM) is revolutionizing how designers, engineers, manufacturers, and end-users create, fabricate, and interact with products. It enables the fabrication of complex parts with novel mechanical, thermal, electrical, and optical properties not found in any natural materials. In addition, AM has spurred development of novel design and analysis tools that can handle the extreme intricacy of AM parts. By combining powerful computational tools with the rapid turnaround of AM, new products can be created at breakneck speeds. However, there are still several barriers to widespread adoption of AM technologies, including a lack of reliable mechanical models. This research investigates the most widespread AM process: material extrusion of polymers. Despite its extremely low cost, material extrusion is rarely used for production-grade parts due to its high anisotropy. Being able to predict the anisotropy will lead to greater adoption. However, existing mechanical models for material extrusion parts tend to be empirical or numerical without explaining the fundamental origin of observed anisotropy, leading to results that differ from printer to printer. This work proposes a geometric explanation for the anisotropic mechanical properties found in material extrusion parts. First, this work investigates the mesostructure of material extrusion parts and provides a parameterization for the void geometry. Next, a closed-form constitutive model is developed based on the void geometry and porosity. Numerical and empirical studies conducted show the closed-form model is accurate within 10% for porosity values below 10%. Finally, the model is used to develop a hybrid stress-aligned/concentric infill scheme that accounts for optimal print path orientation as well as printability constraints. The hybrid infill scheme is evaluated against a baseline rectilinear infill scheme for the classical open hole notch test, yielding 9% higher stiffness and 8% higher strength than the baseline rectilinear infill.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Chen, Ruiqi |
|---|---|
| Degree supervisor | Senesky, Debbie |
| Thesis advisor | Senesky, Debbie |
| Thesis advisor | Borja, Ronaldo I. (Ronaldo Israel) |
| Thesis advisor | Chang, Fu-Kuo |
| Degree committee member | Borja, Ronaldo I. (Ronaldo Israel) |
| Degree committee member | Chang, Fu-Kuo |
| Associated with | Stanford University, Department of Aeronautics and Astronautics |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Ruiqi Chen. |
|---|---|
| Note | Submitted to the Department of Aeronautics and Astronautics. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/yy514rd6522 |
Access conditions
- Copyright
- © 2021 by Ruiqi Chen
- License
- This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).
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