Spaghetti Bridge Glue and Spag Tips Presentation

Spaghetti Bridge Glue and Spag Tips Presentation

Spaghetti and Glue as Building
Materials
David Dobson, Electrical Engineer, USQ
graduate and 3rd place in the 2013 Thiess
Spaghetti Bridge Competition, RME
How Spaghetti was chosen
• Purchased all available
spaghetti- differing
brands and sizes
• Stress test
– Horizontal load
– Vertical load
• Compression
• Tension
• Weight held ---------------------- Weight of 10
strands (equal length)
Choice of Glue
• PVA
– Slow drying
– Strong bond
– Fill voids
• Hot Glue
– Fast drying
– Weak bond
– Fill voids
• Superglue
– Fast setting
– Strong bond-low shear
– No voids
Behavior under tension
• Badly
• Brittle
• Not predictable
Necessary to build a prototype?
• YES
• Partial build of main
features
• Test out Glue
• Test out spaghetti
choices
Management of brittleness
• Design
• Tried to reduce amount
of tension
– More spaghetti under
tension than
compression
– Shared between more
strands
• Keep straight
– Direct forces
– Reduce/remove bending
forces (shear?)
• Shorter multiple pieces
under tension
Spaghetti inspection
• Flaws or imperfections
in spaghetti
– Cracking
• Longitudinal
• Lateral
–
–
–
–
Necking- Narrowing
Curvature
Discolouration
Contaminates
• Is derived from raw
materials – expect
contaminates.
Troubleshooting
• Spaghetti shrinks when
dried.
• Don’t let dry unevenly
• Use spaghetti from
same packet
• Store spaghetti with
bridge
• Atmospheric conditions
make a difference
Troubleshooting
• Ensure feet of bridge
seated if rigid structure
• Don’t use excess glue
Formers
• Good in theory
– Glue sticks
What to do with excess spaghetti?
David Dobson
[email protected]
References
• http://pages.jh.edu/~virtlab/bridge/truss.htm
• http://jeramypaxton.com/2013/05/project-rc-kite-initial-testing/
• http://www.lloyd-instruments.co.uk/Accessories/Foodtexture/Pasta-Rice.aspx
• http://en.wikipedia.org/wiki/Cyanoacrylate
• http://ilovebacteria.com/spaghetti.htm
• http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.95.09
5505