Modal Frequencies

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

When i do modal analysis, the first few modes are in small number e.g 3,4,5 etc.. and quickly jumps to a higher number, if this is the case, can i skip the first few modes and optimze the object for the first highest frequency?

I have attached a picture for reference. Thank You in advance. 

For  the below case, in the first 3 modes, the mode shapes are not significant.

<?xml version="1.0" encoding="UTF-8"?>image.thumb.png.f701b547c4b04ade4a878a88cab8d92a.png

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Answers

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited November 2017

    As far as frequency is increasing no need to worry.From OptiStruct please refer frequency & weighted freq card to maximize frequencies. PFA screenshot from help.

    For optimization specific queries i am moving this topic to OptiStruct.

    <?xml version="1.0" encoding="UTF-8"?>Maximize Freq.JPG

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2017

    Hi @Sarujan,

     

    I worked on your model last Friday. Since the first few modes are very less I tried constraining other modes and had some results. I will share the results with you soon 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2017

    Thank you all for your help,  this is much appreciated.

     

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