Another Science Project


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Well, the other one didn't go so well. It landed on its side and went caput! Oh well...For this one:

Materials:

  • Curugated Cardboard Strips, no longer then 6" no wider then 1"
  • Any Adhesive - NO TAPE

Goal: To build a structure to support a brick :surrender:

Restrictions:

  1. Cannot glue strips together vertically
  2. Device must 16" minimum
  3. Max Weight: 150 g.
  4. Need Paperwork - 5 different ideas, with 5 different descriptions

So, If you guys could help me, that'd be great!

Also, I have a thread at G2G: http://www.geekstogo.com/forum/index.php?showtopic=78054

Danny :thumbsup:

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I must be missing something 'cause if you just take a 6x1" strip and bend it zig-zag style, it will support a brick. No further engineering needed.

OH! A bridge that supports a brick. Entirely different than what I was picturing. And beyond me! It looks like you're on the right track with triangulation there.

Edited by JDoors
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Lemme think on it and I'll get back to you.

This is what I was originally trained in, Structural Engineering, so I can tell you that triangulation is definately the correct path here. That, and an Arch, are the stronger elements in construction.

You need to transfer and distribute the brick's weight over the entire structure, or to the structure's strongest element.

Just need some clarification here tho, "Cannot glue strips together vertically" means....along the long edges?

Edited by Chappy
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Lemme think on it and I'll get back to you.

This is what I was originally trained in, Structural Engineering, so I can tell you that triangulation is definately the correct path here. That, and an Arch, are the stronger elements in construction.

You need to transfer and distribute the brick's weight over the entire structure, or to the structure's strongest element.

Just need some clarification here tho, "Cannot glue strips together vertically" means....along the long edges?

Would an arch be possible w/o gluing them together verticly?

Is this a teacher assigned project? IMO in makes no sence. Why would someone need a bridge designed where they couldnt have vertical supports?

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Here's my fist thought

Glue 3 or 4 (depends on weight) strips together at the ends, overlapping about 1/2", alternate the overlap as in #1

Make 2 similar beams like that, then box them on the ends (#2) and connect them with triangular strips (#3), and a strip across each side for stability.

1.bmp

_2.bmp

_3.bmp

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You know, we shouldn't be doing this for you Danny, it's for you to learn from, but we can't help ourselves ;)

In my post above, one of the most important elements is the strip along the side/sides as it creates stability and stops the triangular strips from collapsing.

I guess you only need 3 strip top & bottom rails, which would span 17" and save weight.Of course the structure stands on the 1" edge, and so does the brick when placed on it. This should easily support the weight with the side strip making sure the supports don't bend.

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Hey Dave,

My mind hasn't "processed all of the info yet, but from the last bmp, it looks like it might not work. I'll ask my teacher, but I don't think that it will be able to work. I think I need to have the brick stick up on a string through it.

Attached is what I think I need. If I could, should I get it to wrap around your idea?

JDoors, I don't wanna cheat :( I NEED a good grade on this, but thanks,

Danny :thumbsup:

_2.bmp

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Hey Dave,

My mind hasn't "processed all of the info yet, but from the last bmp, it looks like it might not work. I'll ask my teacher, but I don't think that it will be able to work. I think I need to have the brick stick up on a string through it.

Attached is what I think I need. If I could, should I get it to wrap around your idea?

JDoors, I don't wanna cheat :( I NEED a good grade on this, but thanks,

Danny :thumbsup:

Ohhh...I thought it just needed to support a brick, as in just put the brick on top of the structure. If the structure needs to support a hanging brick, then it is a different thing you need. I'll think of something later, I need to go right now, but I'll have an idea for you later.

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Oh yeah, hanging from a string will be another matter entirely. Having the entire weight of the brick concentrated in one place, the width of the string ... Whoa.

Can any of the structure hang below the level of the supports on either end? Like the following (don't make fun of my hand-drawn lines!):

brickbridge3jl.jpg

The structure above is to spread the weight of the brick out and the structure below is to prevent the span from collapsing.

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Come to think of it, if hanging structure below is unfeasible, couldn't that part go on top of the span and the inverted "V" go on top of that?

Edited by JDoors
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Danny, if you're using plain old brown cardboard,(in fact don't use coated/colored stuff because the glue won't penetrate) the yellow wood glue will work fine. (it's wood after all) Just be sure to give it time to dry... Like, don't build until 1AM and try the test at 10AM. heh heh....

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I agree plain wood glue (like Elmer's) should work as the strength of the glue bond isn't going to be the deciding issue, preventing the cardboard strips from bending and collapsing will be. That will happen before nearly any glue you use will fail.

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On second thought, though it won't technically be a glue failure, the glue will be stronger than the cardboard so the cardboard may tear at the bonded point. It might be easy to mistake that for a glue failure but the glue bond won't have broken, the fiber bond of the cardboard will though. Just so ya know in case it happens.

Edited by JDoors
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