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I want professional feedback on my work -- Building Model Structures

  1. Mar 8, 2017 #1
    Hello, I am The Maker.

    I am here because I want professional feedback on my work. I have been building things with K'NEX and popsicle sticks since I was little and as a future engineer, I wanted real engineers to evaluate my potential. Please be honest, I am trying to improve my engineering. Please let my know what engineering category this falls under.


    Thank You
     
  2. jcsd
  3. Mar 8, 2017 #2

    Baluncore

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    Welcome to PF.

    General Engineering is OK for structures, then Mechanical Engineering for moving linkages and machines. But don't worry, things can be moved if needed.

    Keep this thread going, drag and drop a compact picture file of your work onto the edit window.
     
  4. Mar 8, 2017 #3

    berkeman

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    Welcome to the PF.

    What's K'NEX? Kleenex?

    How do you design the things that you build? Do you do drawings and mechanical force analysis? When you post a couple pictures, can you also post your design documents for the structures?

    You can use the UPLOAD button in the lower right of the Reply widow to upload files from your computer to the PF thread.
     
  5. Mar 8, 2017 #4

    Baluncore

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  6. Mar 8, 2017 #5
    Sorry about that, here are two videos of my work.

     
  7. Mar 8, 2017 #6

    berkeman

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    Very cool. :smile:

    The wooden tower is beautiful, with a lot of artistry in it. Nice work.

    On the falling metal ball structure, can you see how it moves and distorts as the ball bounces its way down the paths? That's something that you would like to figure out how to prevent. You want to design the structural members to be strong in the directions that they take forces (in compression and in tension). Can you see any ways to brace the structure better to minimize the movement as the ball bounces down the paths? :smile:
     
  8. Mar 8, 2017 #7
    Thank You,
    The reason that the ball seems so unstable, is because it has not a standard K'NEX ball. It is a Fushigi Ball. I ran out of pieces to brace the structure, so that is why it is unstable. The normal K'NEX balls hardly weigh anything, but the Fushigi Ball weighs 14.4 ounces. this makes a huge difference on the structural integrity. I like using the heavier ball because it allows you to do more work on the system per run.
     
  9. Mar 8, 2017 #8

    berkeman

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    Yes, using the heavier ball is better anyway, since you want to learn more about engineering and the mechanics of structures.
     
  10. Mar 8, 2017 #9

    anorlunda

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    I too like your stuff, and your curiosity about the engineering of structures.

    Adding more pieces is not the only way to brace things. Consider this drawing of a sailboat.

    Standing-rigging3.jpg

    Nor is the method of bracing the only interesting question. How is the ball's motion different with a braced or not-braced structure? Does the ball reach the bottom faster or slower?

    You could also treat it as a puzzle. Holding the number of K'NEX pieces constant, how to arrange them to make the stiffest structure? That is like an engineer trying to make the best design using a fixed budget.

    Would you like to learn how to calculate the stresses in different parts of your structure?
     
  11. Mar 8, 2017 #10
    Yes I would.
     
  12. Mar 8, 2017 #11

    anorlunda

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    Good, the purpose of that question was to see what kinds of things interest you.

    I don't know what school grade you are in. But I have another experiment you can try. I think you will like the following article. It should give you ideas on how to build better structures. It also introduces very interesting methods for analyzing structures mathematically. I would like to hear your reaction after you read it.

    https://en.m.wikipedia.org/wiki/Truss
     
  13. Mar 17, 2017 #12
    Sorry I took so long to reply, but I am currently reading it and will get back to you tonight or Sunday eastern time.
     
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