Your challenge is to build a bridge structure, using the Truss Applet, that will minimize the tension and compression. It will be measured by the largest number of tension or compression on your bridge. The person with the lowest number wins!
The Limits:
- You must have two nodes as supports on either side of the structure.
- You cannot place any loads on your supports.
- One of your supports must be a fixed node.
- The other support must be a horizontal rolling node.
- You can have no more than 25 members.
- You can have no more than 14 nodes.
- Your structure MUST hold 100 pounds (in the form of load(s)) downwards.
- In addition, your structure MUST hold a 20-pound load to the right.
What do we mean by "minimize your maximum tension and compression"?
This simply means that you first find your largest value for both compression and tension on your first model. The second model you get, also find the largest value. Then, you compare the two, and find the smallest value. For example:
When you enlarge this, you'll be able to see that the largest compression value is 83, and the largest tension value is 74. We'll compare this to a model similar to this one.
In this second model, the largest compression value is 121 and the largest tension value is 72. By minimizing the maximum value, we'll just take these two upper values and compare them, taking our lowest value as the minimum.
| Minimizing the Maximum Value |
|---|
| Compression Maximum, Example 1 | Compression Maximum, Example 2 | Tension Maximum, Example 1 | Tension Maximum, Example 2 |
| 83 | 121 | 74 | 72 |
In this example, our compression value would then be 83, and our tension value 72.
And the challenge BEGINS....
If this is being done in a classroom environment, or with a larger group of people, click here for both an internet database, as well as a downloadable version from Microsoft Excel. This allows you to take the values for multiple groups.