Error 318 during Optimization

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

Hello all,

 

I'm trying to carry out an optimzation with optistruct with applied forces and displacement contraints but come across error 318. The attached images show the BCs desired and my settings for the SPCs.

During the Analysis step, the process completes without any error but the optimization step returns following error:

*** ERROR #  318 ***  Static load case  1   has nonzero applied loads & prescribed displacements. Optimization with compliance cannot be performed.

 

Somebody who can guide me about this issue? Thanks for your help, suggestions as well as advice!

regards.

 

 

<?xml version="1.0" encoding="UTF-8"?>BCs.jpg

<?xml version="1.0" encoding="UTF-8"?>SPC.jpg

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Hi,

     

    Try this,

     

    constraint all DoFs and run optimization.

     

    I think there is no stiffness force due to SPCs.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Hey Prakash,

     

    Thank you for your answer.

    Actually i have already done the optimisation with all DoF constrained in the middle holes, it is ok, i got the result.

    But for a precise result i need to simulate the real boundary conditions, which only allow a Ratation around Z axis in the middle hole, and then a displacement constrains in X direction in the both side holes. This constrains combination make the part fully constrained. All the DoFs constrained with SPC.See picture below for the coordinaiton.

    And then came out the error 318, after searching i found that there are almost no explanations aout this error.

     

    I am looking forward for further Help

    regards,

     

    <?xml version="1.0" encoding="UTF-8"?>Bild1.png

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Hi,

     

    I am a bit confused with the loads. Is it possible to share the model here?

     

    or atleast the .out file?

     

    Some how there is a moment created around Z axis which makes it a structure with zero stiffness around that.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2020

    Hello,

     

    here is the .out file for analysis and optimisation. Unfortunately the model ist not allowed to share.

    thanks a lot

     

    regards,

    Unable to find an attachment - read this blog

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Just to check, Can you remove the Dx and have only force in -X axis for optimization. If this is through then there is some moment is created because of the enforced disp.

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