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.
1) You must design the “platform” for the weights so that it is 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)
- 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.
The goal of our cantilever was to spread the pressure caused by the heavy objects throughout the structure, and into the shelf. To do this, we sketched out possible scenarios and blueprints for how we thought the energy should be propagated.
It is important to know that none of us have any engineering/architecture background, the concepts were purely thought from the head, and replicated on paper. Because of this, we ended up with a design centered around a super structure (is what we call it). This super structure served as a strong mass that could hold its branches in place.
(With the super structure in the middle, we started planning the height of the construction as well. As you can see, the poles are reinforced by adding more wood instead of just 1 rod)
We proceeded with a post-and-lintel type of pattern, very basic and highly inspired by KAPLA, a wood construction game that we played when we were younger, as well as Japanese vertical and horizontal architecture.
The long arms that make the CantiLever were built by binding many wooden rods together, and applying the Elmer’s glue as binding, much like ciment. The string you see in the above picture bound the thick arms to the long rods that were “stretched” across the entire length of the construction.
* very important *
These rods were then aligned with the arms, passed through the super structure, and bound to the back. The interesting part is where the rods meet the super structure. The post-lintel pattern enabled us to pass the rods THROUGH the architecture, while the horizontal rods kept it squeezed and tight into place. No glue needed on this area of the project.
When we brought the structure to test out in class, we were amazed by how much weight it could hold. We held the proud position of 2nd place. As expected, the CantiLever snapped around the base of the arms and superstructure, right where the wood meets the corner of the shelf.