Design, development, and characterization of an experimental device to test torsion-controlled fracture of thin brittle rods

As research continues to uncover the many different physical properties of meso- and microscale materials, it becomes more evident that these materials often behave in counterintuitive ways. Characterizing unique phenomena not only provides analogies in nature which inspire innovation at all levels of research and design but also presents new possibilities for future technological development. The discussion presented herein explores the design and development of a low-cost, manual device intended to test a hypothesis rooted in the behavior of breaking pasta that intrigued even Richard Feynman. While the mechanism for why spaghetti breaks into three or more pieces has been described, the experimental discussion presented here focuses on the effect that added torsion has on the fracture bent spaghetti. Specifically, it is possible that twisting the spaghetti a critical angle and bending it will cause it to fracture into only one piece. The idea of torsion being used to exhibit some control over how a material fractures has not been well-investigated; the results which come from this experiment may prove useful for applications even beyond the scope of thin brittle materials. With this said, the sensitivity in quantifying breaking from torsion and bending together requires that the experimental device prevent systematic error stress from negatively impacting the accuracy of the experiment. Thus much time is devoted to explanation and rationale behind the analysis of the experimental device. Alongside the device's characterization this thesis serves to be a reflection of the design process taken while creating this device. Lessons learned from this project are included in all aspects of the discussion and a section in the Appendix is devoted to a more detailed account of the design and fabrication of one device component.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2016

Author dc:creator

• Heisser, Ronald Henry

Advisor dc:contributor.advisor

• Jörn Dunkel.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/105705

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/105705