Type
Text
Type
Thesis
Advisor
Sampath, Sanjay | Dwivedi, Gopal.
Date
2016-12-01
Keywords
Materials Science -- Engineering | Bio-Inspired, Crack Growth Resistance, Fracture Toughness, Hybrid Composite, R-curve, Thermal Spray
Department
Department of Materials Science and Engineering
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76253
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Nature has presented a remarkable bill of materials which show excellent mechanical properties. Among those which have been extensively studied are wood, bone, rocks, spider silk, nacre etc. Interestingly all of these materials are primarily known to have great fracture resistance and present excellent example of natural and layer-by-layer evolution of materials. These materials have inspired the current research society to synthesize new generation materials with mechanical properties beyond the conventional materials such as metal, ceramic and polymers. Nacre, one of the most researched natural materials, is present in particular sea-shells and shows a layered brick-and-mortar structure. Designing nacre-like structures has been a goal of many researchers due to the combination of its high strength and toughness. Thermal spray, a melt deposition process, has the ability to produce similar structures which can exhibit mechanical behavior similar to nacre. With an appropriate selection of process conditions, a nacreous brick-&-mortar structure can be synthesized. The structure is consisting of 95 vol% of CaCO3 tablets with a brick wall arrangement with 5vol% of bio-polymer serving as a mortar between tables. Although, there have been several attempts by other researchers in the past, many other attempts have been made to synthesize such a material, they remain limited to a laboratory scale dimensions and are challenging to be scalable. While thermal spray, a readily scalable and industrially adapted process, shows no limitations with the development of nacre-like structures over a large surface area. Previous work down by the group has produced such a nacre-like structure using a flame spray process, one of the variant of thermal spray which uses rod as a feed, resulted in similar mechanical behavior to that of nacre. The work demonstrated that these templates along with the introduction of a polymeric epoxy, the fracture toughness and strength can be raised up to the values of a real nacre. Although, the fracture toughness was primary property of this study and the values were well matched, the fracture behavior found to be somewhat different between the hybrid composite and nacre. In particular, the hybrid composite was unable to exhibit any significant toughness under slow crack growth conditions, which is the most attractive feature of nacre. This thesis focuses on first investigating the toughness in the sprayed hybrid composites by using standard resistance curve (R-curve) measurements. The study then focused on developing thermal spray modified hybrid composites with improved toughness, as well as with higher application temperatures, beyond the limitation of epoxy. | 81 pages
Recommended Citation
Resnick, Michael Murray, "On the Fracture Toughness and Crack Growth Resistance of Bio-Inspired Thermal Spray Hybrid Composites" (2016). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2184.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2184