ERROR # 2148

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

Hello, I am confused about something. I receive this error from optistruct when trying to run topology+shape optimization.

 

 *** ERROR # 2148 ***
 Invalid design problem.
 All the sensitivities of response 2 (objective) are zero.

 

This is a 3d hex element model that I created from extrusion of pshell elements. I only want to run optistruct with the hex elements, since the pshell were just used as reference to create my hex elements. Optistruct will only run if my pshell elements are turned on. As soon as I turn them off, running optistruct gives me this error message.

 

I have attached the .hm file here.

 

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    Hi, 

     

    I think during optimization material is removed all over and solver ends with the error.

     

    Try to create a non-design space and move elements where loads and boundaries are applied or change the bounds on the volume frac.

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    I have deleted the 2D element and I am able to run the optimization.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    I created a non-design space and moved some elements there, but I am still getting the same error message.

     

    I have also tried creating a new duplicate property for the non-design elems, since the topology variable seems to be assigned to properties (not components). This also resulted in the same error message.

     

    Did I follow your advice incorrectly?

     

     

    on a side note, can you tell me why a component contains property and material info? The material is already included in the property.

     

    Thank you very much.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    Sorry, here is the file that I described.

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    Hi,

     

    You are trying to use the mode which has a frequency of almost zero. 

     

    Try a bigger mode. I have shared a model file with you. Please check the same. 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    Thank you, Ill have a look.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    Hi @Bertoni I have shared the modified file via Email.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018

    Yes Prakash, thank you I have received it and understand how to make it work. I really appreciate all your help, thank you.

     

    In regards to topology optimization, can you tell me if stiffness changes is taken into account, when material is removed? Modulus & volume are the drivers for stiffness, and those don't seem to change with topology.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2018
    Altair Forum User said:

     

    In regards to topology optimization, can you tell me if stiffness changes is taken into account, when material is removed? Modulus & volume are the drivers for stiffness, and those don't seem to change with topology.

    Hi,

     

    I think yes, you can see the change in the compliance in the out file. 

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