General Mechanical

General Mechanical

Behaviour of Point Masses in Modal Analysis

    • BassaSelim3
      Subscriber

      Hey everyone,

      How do Point masses effect a modal analysis? How does Ansys handles the stiffness of the point mass as the eigenfrequencies and eigenvectors are calculated?

      Is the Point mass represented as a node?

      Thank you for your help

      Kind Regards

      Bassa Selim

    • Erik Kostson
      Ansys Employee
      Hi

      I think this has been asked, so there is a lot of info on this forum and on the web - please search.

      If we look on the input file (ds.dat) generated by ansys (which is what goes to the solver) when we use a point mass, it will use a mass21 element ((this element has only one node)) for the point mass, a contact (say conta174) element for the surface where the mass is related/scoped to, and a target element (targe170) for the element where the mass21 is (use same node often as mass21 element). Then we change the key options for the contact and target elements depending if it is deformable or rigid and so on. Depending how the contact is set it will add (rigid) or not add stiffness (deformable) to the scoped face and that comes via all these above settings and the solver accounts for that then once we have defined it.

      As we said see the forum and web and the help for details.

      All the best

      Erik
    • BassaSelim3
      Subscriber
      Hi Erik thanks for the explanation.
      Kind regards
      Bassa Selim

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