Classroom Activity: Unstable/Stable Structure

 

To Do

1. Design and build an interesting, unstable structure.  You do not have to show any calculations.  The goal is simply to create an interesting structure and show the sometimes subtle difference between a stable and unstable structure. 
2. Figure out an interesting way to make it stable.  
3. Photograph your model in its unstable and stable forms.

 

Examples

An example of modeling planar mechanisms from cardboard can be found here. 

Fall 2011 Team 2's model of a roller support:

Supplies

• poster board (to serve as structural members and ground)
• paperclips (to serve as pins)
• scissors
• rulers
• push pins (to punch holes in poster board)

 

Results

Team	Unstable Version before loading	Unstable Version after loading	Stable Version	Stabilization Technique
1				add bar
2				add bar
3				add bar
4				add bar
5				add 2 bars
6				add pin support     (at middle right)
7				add 2 bars
8				add bar
9				add bar
10				add 1, 2 or 3 bars
11				add pin where bars cross
12				add bar
13				add bar
14				add bar
15				rigidly connect 3 bars (by adding push pin to existing joint)