bernard wrote:Daquan wrote:Has anyone found some successful ideas for the bridges?
If you're asking about design, there is no one best design. Some of the bridges that placed at nationals last year looked just like mine and others looked nothing like it. The best recommendation I can give is start with a design you like and think will do well (if you don't know what will do well, do some reading or look at pictures of bridges). Then test it, observe it as it is loaded and fails, then make more. Don't change a whole lot as you work towards a successful design or you might not know what's good. Students I've talked to who have done well in the event in the past have made many bridges.
SPP SciO wrote:Curious: has anyone ever built or seen a single-piece bridge? A student suggested starting with a single block of balsa and creating a real fancy looking bridge through subtraction..
On one hand, I think it's really interesting, and not impossible- drills, coping saws, hours of careful sanding ... On the other hand, it's a significant investment of time and money - Any thoughts before setting some kids loose on this project?
UnprunedShrub wrote:Wouldn't that kind of bridge be really weak? In a normal bridge, the grain is parallel to each piece, but in a single piece bridge the grain would be all messed up and could even be perpendicular to the member and would split easily in those locations. It would probably also waste a lot of wood and it would be really hard to make a bunch of these bridges. If you really want to go through this idea, I would suggest that you laser cut your bridge instead of trying to do it by hand.
SPP SciO wrote:Great points, thank you. I think I will have the students try the idea by building small hollow cubes, one from 12 sticks and one carved from a block - will post results if/when results come to fruition!
andrewwski wrote:I've seen teams laser cut them from balsa sheets before - they generally don't seem to do well. The grain is the biggest issue - you want to load along the grain, but there's no way to do that when cutting all from one piece. It can also be harder to avoid imperfections in the wood.
Unome wrote:andrewwski wrote:I've seen teams laser cut them from balsa sheets before - they generally don't seem to do well. The grain is the biggest issue - you want to load along the grain, but there's no way to do that when cutting all from one piece. It can also be harder to avoid imperfections in the wood.
You're still active!
Back to the topic: the only time I remember hearing of a laser cut piece was at last year's Nationals (I think the picture is on the Best of Nationals page)
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