Tag Archives: Structural Design

Assignment 1 – Balsa Truss Cantilever [Create & Destroy!]

The Task:

The task is simple. Create a structure that extends horizontally from the edge of a stack of textbooks. Next week you will be building the weights that we will use to destroy said structure.

The Rules:

1) You must design the “platform” for the weights so that it is greater than or equal to (>= … this is the mathematical sign for “greater than or equal to”) 12 inches away from the edge of the ¬†surface at the top of the stack of textbooks.
2) The “platform” for the weights must be at least 3 inches wide by 3 inches deep.
3) You cannot have any vertical supports that are touching the ground underneath the structure.
4) No part of your structure can be more than 4 inches below the plane of the top surface of the textbooks. You can build as high as you want.
5) Your structure must have a section to rest on the top of the text books that extends at least (>=) 8 inches away from the textbook edge. This will be where one member of your team place their hands to provide the counter balance. (see diagram)
6) Your structure can only be comprised of:

  • The 30 sticks of balsa wood provided (or less)
  • The amount of glue in the one bottle provided (you are allowed to dilute the glue with water during the building process)
  • no more than 5 ft of “general sewing” cotton thread.

cantilever-challenge

The Competition Procedure:

On the day of the competition (in ~2 weeks), one member of your team will place their hands above the section of the structure on top of the textbooks; this will provide the counter-balance as we add the weights to the “platform” of your structure. We will continue to add weights until the structure ruptures or deforms beyond functional point.

Competition Winners

The team that builds the structure that can sustain the most weight, will win a “special prize”.

The team with the most aesthetic / creative design will also receive a special prize though maybe not.

Additional Comments

Note: Aisen and I encourage you to do anything and everything you can to build the most creative and effective solution to this challenge. If you find a loophole in the rules (a way to hack the system), more power to you!

Some resources you might want to check out:
РAnalysis of Truss Structures:  http://www.ce.memphis.edu/3121/notes/notes_03a.pdf
– Beam Deflection:

http://www.me.berkeley.edu/~lwlin/me128/BeamDeflection.pdf

- Truss Arch Bridge:

http://en.wikipedia.org/wiki/Truss_arch_bridge

- Truss:

http://en.wikipedia.org/wiki/Truss

- Other words you might want to google for ideas: truss, cantilever, beam, structural deflection