Anyone whos prob done this can help me and my group a bit. Obviously its to see who hold the most weight and also compared to weight of bridge to weight it can hold Rules and Terms: We are useing 3/32 inch basswood. Cannot laminate basswood, but can glue together, notche, cut, and sand it. Cannot weight more then 30 grams must be longer then 300 mm shorter then 400mm (basically...its not huge) Taller then 100mm, and must extend below itself 15mm to 25 mm (imagine 2 tables pushed together with a flat bridge on inbetween, there must be bottom part extending downwards) Cannot be wider then 80mm MUST have arch-type or an A-frame And it will be put to the test with small wooden block with a hook which you hook on the weights. The stress will be put in the middle of the bridge (does not need to be like an actual bridge...as in there does not need to be a place where a "car" would have to travel through, thus you can make some weird square thing to help hold weight holder thing) The place where the weight holder will be put on will be 5 to 10 mm above the supporting surfaces... Anyone got any good ideas besides "Triangles are the strongest"?
I have a few ideas but notching the wood at that tiny of a size is nuts (just some basic wood working things) you have access to a laser cutter?
We did this group for Mr. Hamilton's physics class in 11th grade, my groups bridge held the most weight. If I can find some pictures I'll post them, but basically our whole structure was under the platform and we had arches running through the middle of our rectangles that ran the length of the bridge for more support.
|..........____________________ .....| |...../..................................... \...| |../.......................................... \.| |/............................................. \| Ignore the dots, they were so the spaces would stay The box being the rectangle that spans the length of the bridge, one per side, and that funky looking crap in the middle is supposed to be an arch. With that it supports the very center of the bridge, where you would choose to put the holder on the the weight dangles from. Worked well for us.
I wish I could help. Basically I'd just start building and see what I could come up with. I guess I'm really a trial and error sort of person. :dunno:
A CRUDE drawing.... We are trying to put ALL the weight on the very top of the arch...the arch can only 3.5 cm tall though (maxed), thus a tight fit on the 2 ends of the table
That's roughly the design we had, but when we did our arches we doubled it up with 2 (one under the other). We also had a flat laoding point (it was the requirement for the project that year). Then we threw in as many triangles as we could, even between the arch and the rectangle it was implanted in. We also won the best looking bridge award, securing my A in the class . Viel Gluck (good luck)! Craig
Triangles That was basically what we did, from what I remember. However that was 2 years and thousands of beers ago, my memory could be shot to hell by now. Craig
When I say that I mean I was in 10th grade and just had ideas about what worked best, from looking at real bridges and crap like that. But our bridge held more than any bridge did that entire year at our school, so that's gotta count for something. And actually the triangles up top would help, because it would stop the whole bridge from bending too far down in the middle. It will help keep it more stable and rigid, which will help it hold for a little bit longer. Craig