INTRO
In this project, we were asked to make a bridge out of 5 balsa sticks and glue only. you had to design a bridge with onshape then print put a blueprint of it and build it off that. once you had built your bridge and glued it you had to wait at least a day for the glue to dry then we could test how much weight our bridge could hold. we put our bridge on a miniature abutment and attached a crane scale with a bucket at the bottom and scooped sand into it until our bridges broke.
Inception and Drafting
I chose this bridge design because it seemed simple to make and had the potential to hold a lot of weight. Drawing it in onshape wasn’t too difficult I mostly just drew what I wanted and then dimensioned it after I had finished it. The part that was hard was making sure I had enough wood to actually build the bridge
Bridge Building Phase
The steps to make the bridge were to 1. Make a model using onshape of your bridge, 2. print out a scaled blueprint of the bridge, 3. Cut your wood and line up the pieces with the paper, 4. glue everything together, 5. make another side to your bridge, 6. glue support beams in between the two sides, wait for everything to dry, and then you’re done.
Destruction Phase
Testing my bridge didn’t go too well for me. I had glued the support beams in a very slight slant so that caused my bridge to just fold and slip out of the bridge abutment. It only held 5 kilograms before it fell but I think that if I had glued the beams correctly it could’ve held a lot more weight
- CONCLUSION
- How many members does your bridge have? 46
- How many nodes does your bridge have? 26
- How many linear inches of balsa wood were used to make your bridge? 180 inches
- What was the weight (N) of your bridge (remember, weight is a force due to gravity and F=ma)?144
- How much weight (N) did you test your bridge to and did you test to destruction? 1.412064N
- What was the strength to weight ratio (max load (N)/ weight of bridge (N)) of your bridge, 34.722
- Plot load (N) versus deflection (mm) for your bridge.
