NESTED LOADING in OPTISTRUCT

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

Is it possible to apply and run nested preloads.

Like, if i have 4 subcases and i want to carry the result of subcase 1 on 2 and so on.

subcase 1 as preload in subcase 2

subcase 2 as preload in subcase 3

subcase 3 as preload in subcase 4.

I tried to get result by taking types: Linear and Quasi-Static Analysis but in-vain. As per my best knowledge it is possible in Nastran, Ansys and Abaqus with Quasi-Static Analysis type.

Answers

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited August 2014

    Pritam,

     

    Did you try prestressed analysis first with just two of your subcases? is that what you were looking for? also are all your loadcases linear static? in the Hyperworks help see

     

    Altair OptiStruct > User's Guide > Structural Finite Element Analysis > Loads and Boundary Conditions:

    Prestressed Analysis

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2014

    I believe what you are looking for is the  'CNTNLSUB' option. You can activate it by card editing the desired loadstep and checking 'CNTNLSUB', which is right below 'ANALYSIS'.

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited August 2014

    Yes, but please note CNTNLSUB is for non linear loadcases only, 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited August 2014

    CNTNLSUB is for non-linear subcases that i understand how its works. But when i was tring for Linear Static :

    Pretenstion load as STATSUB(PRETENS) in 1st load case

    and later : 1st Load case as STATSUB(PRELOAD)to 2nd Load case and so on till 4th subcase.

    But during the run, Optistruct run came out by giving error Nested Looping, So i thought, i can clarify whether optistruct supports nested looping or not as in the case of NASTRAN.

    Later, i decide to run with work with CNTNLSUB and changing load cases for LINEAR STATIC too as it's the only work around option.

    Thanks for response.