Damping in Nonlinear Transient Analysis

cfuser
cfuser Altair Community Member
edited October 2020 in Community Q&A

Dear all,

I am currently working on a transient analysis (not modal analysis!) and want to introduce damping to the model. I figured that damping can be added through PARAMs. Using PARAM, ALPHA1 and ALPHA2 will add Rayleigh-damping is that correct? If so, is Rayleigh-damping by itself sufficient when one wants to add damping to a model? Further, there are PARAM, W3, W4 and G that can be used for adding damping. Could I alternatively use these parameters to successfully introduce damping to the model? Or is it necessary to use all the parameters simultaneously (ALPHA1, ALPHA2, G, W3, W4) to achieve sufficient damping?

As always I'd be really grateful for any help!

 

Cheers,

 

cfuser

 

PS: I have looked into the OptiStruct online help and found it a bit confusing. Can someone give me a quick and simple explanation of the parameters involved (ALPHA1, ALPHA2, G, W3, W4)?

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Answers

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited November 2019

    Damping

    This Nonlinear Transient solution sequence currently only provides support for Rayleigh Damping. The damping parameters can be input using PARAM, ALPHA1 and PARAM, ALPHA2. Subcase-dependent parameters can be input using the Alpha and Beta fields on the TSTEP Bulk Data Entry. 
     

    Use of G, W3, W4 is mainly for linear dynamic analysis.

  • cfuser
    cfuser Altair Community Member
    edited November 2019

    Hello Rahul,

    thanks a lot for this quick reply! Ok, so I'll just use ALPHA1 and ALPHA2 then.

    Cheers,

     

    cfuser

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