Number of modes for free free run of 4 noded shell element

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

How many modes does a single shell element - 4 noded (i.e. linear) have if a free free run is carried out?

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited September 2016

    Hi Niks,

     

    4*6= 24 modes.

  • Q.Nguyen-Dai
    Q.Nguyen-Dai Altair Community Member
    edited September 2016
    Altair Forum User said:

    How many modes does a single shell element - 4 noded (i.e. linear) have if a free free run is carried out?

    If you're speaking about 'Modal Analysis', for any structure of 'free-free' type (whatever number of element), you have to have exactly 6 rigid modes of vibration.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited September 2016
    Altair Forum User said:

    If you're speaking about 'Modal Analysis', for any structure of 'free-free' type (whatever number of element), you have to have exactly 6 rigid modes of vibration.

    Yes, the first six modes or the modes with Frequency near zero are rigid modes.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited September 2016
    Altair Forum User said:

    Hi Niks,

     

    4*6= 24 modes.

     

    Thanks very much Prakash. 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited September 2016
    Altair Forum User said:

    If you're speaking about 'Modal Analysis', for any structure of 'free-free' type (whatever number of element), you have to have exactly 6 rigid modes of vibration.

     

    Thanks Q. Nguyen-Dai.

    I was needing answer for total modes. However, as Praksh said, it will have  total 24 modes.

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