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Thread: Impact Energy of a Hammer

  1. #1
    emisnug's Avatar
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    Robert Keyes
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    So, my mathematics has failed me once again. I'm looking to work out the impact force of a hammer, while knowing the ram force, arm length and impact area size.

    Ram Force (at full extension): 10,000N
    Arm Length: 1 Meter
    Impact Area Size: 1 cm x 1cm

    In my mind, this should be crazy simple, but I think I have done it incorrectly, mainly because I don't know what difference the impact area size makes. (Plus, moment arms were a long, long time)

    Could anyone explain it at a 5-year-old's level please?

  2. #2
    Maxamuslead's Avatar
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  3. #3
    emisnug's Avatar
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    And so it has, somewhat. The page doesn't really explain what "l" is, or how the impact area affects it
    Last edited by emisnug; 30th August 2017 at 11:02.

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    There's a few ways to work this out. But do you really want to know impact energy, force or stress? Why?
    You'll need to know the contact area to calculate the stress, the target stiffness or deflection to calculate the force, and you'll need to know the piston travel in all cases to know the energy. That's all assuming your robot chassis doesn't take off/move during the swing, as that can absorb a significant amount of the swing energy. For a low energy hammer that's a fair assumption. for anything competitive, it significant and only a complex model will tell you what the result will be.
    How much energy you've got to play with is fairly easy to calculate: piston force x travel = Energy. (force in Newtons, travel in metres)
    Hammer head weight can come into it a little too. If its a short, light hammer, then the piston will be running at maximum speed, limited by the speed the gas can get into it, so the full energy won't get transferred

  5. #5
    emisnug's Avatar
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    The main reason I want to figure it out is so I know how much energy my feather has the potential to impart (although, other factors, such as lack of skill, play a huge part in that) - plus, I much prefer seeing how things work on paper then bringing that into CAD simulations. I tend to understand them better. (Like, I learned to draft before starting CAD)

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