1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Polar moment of inertia for a shaft with slot

  1. Sep 1, 2010 #1
    1. The problem statement, all variables and given/known data
    HI
    Can anyone help me in finding out the polar moment of inertia of a hollow shaft with 3 circular slots . Its used in design of DIVERTERS in oil and gas application.


    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Sep 1, 2010 #2

    rock.freak667

    User Avatar
    Homework Helper

    Do you have a diagram?

    Do you know the dimensions of the slots? If you do, then you can just subtract the inertia of the slots from the inertia of the hollow shaft.

    J= πd4/32
     
  4. Sep 1, 2010 #3
    The slots are 1.031 long and 0.688 wide Like a Mill Slot . they are rounded at the end(Radius of the rounded ends 0.344). they are 3 slots at 120 degree apart place radially.

    Thanks
     
  5. Sep 1, 2010 #4
    I think the polar moment of inertia for a hollow shaft is J = π(D4-d4)/32 when derived from its center. I have the slots 0.250 distant from the end of the shaft. How does it change the MOI?
     
  6. Sep 1, 2010 #5

    rock.freak667

    User Avatar
    Homework Helper

    I think then, you can assume that they are like cylinders then, and just subtract them from the inertia of the entire thing. But I'm not too sure what a Mill Slot looks like so it is possible that I may suggesting the wrong thing.
     
  7. Sep 1, 2010 #6
    _____
    (_____)

    I hope you got how the slot is looking .
     
    Last edited: Sep 1, 2010
  8. Sep 1, 2010 #7
  9. Sep 1, 2010 #8

    rock.freak667

    User Avatar
    Homework Helper

    Well in that case, I'd just approximate that shape to a cuboid.

    Just find the inertia about its own center and then use the parallel axis theorem to find the inertia about the axis of the shaft.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Polar moment of inertia for a shaft with slot
  1. Moment of Inertia? (Replies: 9)

  2. Polar moment of inertia (Replies: 10)

Loading...