Point mass moment of inertia

Altair Forum User
Altair Forum User
Altair Employee
edited June 2022 in Community Q&A

Very simple question: how can I assign moments of inertia to a point mass (CONM2)? I've done it before but can't seem to find the 'path' to it anymore (which panel/ pull down menu)! Thanks

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2011

    Very simple question: how can I assign moments of inertia to a point mass (CONM2)? I've done it before but can't seem to find the 'path' to it anymore (which panel/ pull down menu)! Thanks

    check out the 'crash-2000: front impact bumper model' step 3 from the tutorials, it will help image/emoticons/default_smile.png' alt=':)' srcset='/emoticons/smile@2x.png 2x' width='20' height='20'>

    Posted Image

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2011

    Thank you very much for the reply. I can't try this out until next week, but I'm pretty sure my point mass didn't have a card assigned to it... At any rate when I right clicked and tried to 'edit card' it said there was no card. I know it's possible to define the inertia through the menu anyway, but I can't remember how!

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2011

    Check which template you currently have loaded or the element type assigned to your element. For NASTRAN, you want CONM2 element type, then when you card preview, should be able to add the inertia terms to the element.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2011

    Thanks, I'll try it out!

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2015

    Hi,

     

    I am using RADIOSS Block 120 solver. I have defined a point mass (elem type M). How can I define moment of Inertia for the point mass. I couldn't find any options to do so in CARD EDIT. Thanks.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2015

    Hi Sai,

    You can define the added mass using admas from 1-D panel and then connect all the nodes of the body using /RBODY

    Please edit the /RBODY card and use the slider to find the ICOG field and also enter inertia and mass.

    ICoG= 1 will add the mass and inertia to the master node.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2015

    Thanks Prakash.

  • gopal_rathore
    gopal_rathore Altair Community Member
    edited May 2016

    Hi,

    I am using block 130 format and have used admas at the CG which is connected to the structure through a rbe 3 element to the structure. Now I want to add Moment of inertia for the mass by keeping the rbe 3 same and not using rbody as I think it will provide stiffness to the structure whereas rbe 3 does not. Is this correct?

    Is there any way to provide MOI in such case. As it is available in optistruct by using combination of rbe 3 and conm2 element and then editing the conm2 card.

     

    Kindly let me know for the same.

  • Shreeyash Vaidya_21828
    Shreeyash Vaidya_21828 New Altair Community Member
    edited June 2022
    Altair Forum User said:

    Check which template you currently have loaded or the element type assigned to your element. For NASTRAN, you want CONM2 element type, then when you card preview, should be able to add the inertia terms to the element.

    How to preview a card ? I know I have asked a silly question but I'm a beginner .

    I have selected Nastran Solver and element type is CONM2

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