_s1.h3d File Iteration 0 Stress Interpretation

Merula_20758
Merula_20758 Altair Community Member
edited October 2020 in Community Q&A

Hello guys,

 

what exactly is the first (0) Iterations stress contour plot? It differs from the stress output you get when doing an analysis.

I am aware, that the topology optimization solver sets the density value euqally distributed over all elements to some start value which is 0.3 I think. But then I would expect to see 3 times the stress in an linear optimization (Iteration0) compared to a linear analysis?

 

Thanks in advance.

Best regards,

 

Merula

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited May 2017

    Hi @Merula

    The material used depends on responses. 

    for example

    The volfrac in first iteration is either 0.9 or 0.6, depending on whether mass is objective or not. The first iteration will be same as analysis results only if the volfrac = 1.0. To get that, set MATINIT = 1.0. Then the results between first iteration should match that of previous analysis.

  • Merula_20758
    Merula_20758 Altair Community Member
    edited May 2017

    Hi @Prakash Pagadala,

     

    so just to get this straight:

    The Volfrac Value is related to the element initial density value. If it is 0.6 (with compliance as the objective), Iteration 0 should have the same as an analysis with 0.6 * E0 ?

     

    Best regards,

    Merula

     

     

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited May 2017

    @Merula

     

    Maybe I should have said as initial material fraction instead of VF. 

     

    So from help, For runs with constrained mass, the default is reset to the constraint value. If mass is not the objective function and is not constrained, the default is 0.6. 

     

    According to help, you are correct, but before I confirm, let me investigate on the same. 

     

     

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