Dissertation
EXPERIMENTAL CHARACTERIZATION AND MULTISCALE MODELING OF THE DEFORMATION AND FRACTURE BEHAVIOR OF CARBON NANOFILLER REINFORCED POLYMER NANOCOMPOSITES
Doctor of Philosophy (PhD), Washington State University
01/2017
Handle:
https://hdl.handle.net/2376/13037
Abstract
Carbon based nanofillers such as carbon nanotube (CNT), carbon nanofiber (CNF), and graphite nanoplatelet (GNP), which possess superior strength and stiffness, have emerged as new potential reinforcement materials for developing advanced composites. Despite the many research efforts that have been devoted to the area of nanocomposites, a comprehensive understating of this new material system is still lacking as nearly all of them have been focused on a specific type of composite or material property. The overall objective of this research is to gain a comprehensive and coherent understanding of the mechanical characteristics and reinforcement mechanisms of CNT, CNF, and GNP and their correlation with the performance of the resultant composites.
To achieve the research objective, the mechanical behavior of a High Density Polyethylene (HDPE)-based composite reinforced with CNT, CNF, and GNP is processed
and characterized first. The load spectrum spreads over both tension and compression for a wide range of strain rates, 10-2-104/s. This part of the work establishes a data base for this research. Following the experiment work, molecular dynamics simulations are used to gain insights on the mechanical characteristics and reinforcement mechanisms of different types of carbon nanofillers. Finally, a mesoscale finite element study is performed to understand the correlation between the reinforcement mechanism and the overall performance of the resultant composites.
It is found that the properties of the nanofillers that make the most significant differences are their interfacial properties and the shapes. For perfect bonding, CNT and CNF perform better than GNP due to their larger aspect ratio and longer critical length which lead to better load transfer capability. However, for poor bonding, the differences between the reinforcements by fillers diminish. For pristine fillers, CNT and GNP have very poor interfacial strength due to their smooth exterior surface. The interfacial strength of CNF is much stronger due to its serrated surface which leads to better mechanical interlocking between filler and matrix. Thus, without any surface treatment, CNF-composites perform better than others due to its better stress transfer capability. The better surface treatments, the closer the performance of the composites to that predicted by the perfect bonding.
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Details
- Title
- EXPERIMENTAL CHARACTERIZATION AND MULTISCALE MODELING OF THE DEFORMATION AND FRACTURE BEHAVIOR OF CARBON NANOFILLER REINFORCED POLYMER NANOCOMPOSITES
- Creators
- YUEQI HU
- Contributors
- Jow-Lian Ding (Advisor)Weihong Zhong (Committee Member)Soumik Banerjee (Committee Member)Jinwen Zhang (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 144
- Identifiers
- 99900581514001842
- Language
- English
- Resource Type
- Dissertation