Compatability with AMS

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

Dear Experts,

 

Can we use /DT/BRICK/CST along with /DT/AMS?? There is nothing mentioned about this in the recommended check list or in limitations-capabilites of advanced mass scaling in the user manual. If I am employing both in my model what time step is TAKEN TO SOLVE in the model?

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2016

    Hi Raghav,

    You can use /DT/BRICK/CST with /DT/AMS.

    /DT/BRICK/CST is used for strain formulation in brick elements and /DT/BRICK/CST will only work for brick property sets with Ismstr = 2. And they don't have any effect on the time step you assigned in/DT/AMS. The solver will run according to the time step assigned in AMS.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2016

    Hi,

     

    Thanks for the response. What could the exact effect of /DT/BRICK/CST in a simulation... Can it be used besides /DT/NODA/CST ???

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2016

    Hi Raghav,

    For solid elements negative volume error happens when solid elements are very deformed and their characteristic length goes to 0. For large strain formulation the time step of an element goes to 0 when the element is compressed. Then we will use small strain formulation for solid elements and the option/DT/BRICK/CST is used thereby setting a time step value tmin at which the solid elements will switch to small strain.  This means that the solid elements will use large strain formulation while their time step remains greater than tmin, and will then switch to small strain formulation when it reaches the tmin specified in /DT/BRICK/CST. You can use it with /DT/NODA/CST