Effect of constraint on mechanical behavior of polymer layers and membranes in energy applications
Abstract/Contents
- Abstract
- The role of mechanical constraint is well known in the mechanical behavior of engineering materials such as adhesive joints and alloys. However, in the case of polymer layers and membranes, the effect of mechanical constraint is not always understood. In particular, in energy technologies, device geometry is becoming increasingly complex but the role of mechanical constraint is not explored. In proton exchange membranes (PEM) fuel cells, the PEM is constrained by the adjacent current collector plates such that the membrane can only deform in the flow channel areas. I showed that the tearing energy decreases with increasing constraint associated with a smaller plastic zone and is much lower than the tearing energy with no constraint. In photovoltaics, the backsheet structure is a layered film where the tearing behavior of the individual layers does not necessarily represent the tearing behavior of the entire backsheet. I showed that such characteristic arises from the interaction between the individual layers during the tearing process, where one layer of the backsheet is mechanically constrained by its neighboring layers and the layers may debond from each other. Finally, I present the mechanism through which mechanical constraint enhances the stiffness of a novel polymer composite electrolyte for batteries. The composite electrolyte is composed of a silica aerogel monolith filled with a polymer electrolyte. When the voids of the aerogel are filled with the polymer, the polymer constrained the bending of the cell wall and effectively enhanced the stiffness of the composite. This work highlights the importance of considering the effects of mechanical constraint as it can lead to surprising effects on the mechanical and fracture properties of materials.
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 | 2018; ©2018 |
| Publication date | 2018; 2018 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Yuen, Pak Yan |
|---|---|
| Degree supervisor | Dauskardt, R. H. (Reinhold H.) |
| Degree supervisor | Sheppard, S. (Sheri) |
| Thesis advisor | Dauskardt, R. H. (Reinhold H.) |
| Thesis advisor | Sheppard, S. (Sheri) |
| Thesis advisor | Cui, Yi, 1976- |
| Degree committee member | Cui, Yi, 1976- |
| Associated with | Stanford University, Department of Mechanical Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Pak Yan Yuen. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2018. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2018 by Pak Yan Yuen
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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