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# Defining frequency dependent constraint in Nastran sol 200

## Defining frequency dependent constraint in Nastran sol 200

(OP)
Hi,

I want to define a constraint for a topology optimization problem that uses frequency value (Nastran sol 200). In the other word the constraint will update for every frequency value during a forced response analysis for each optimization loop. How can I fetch and use frequency value for this job? how can I define a frequency dependent constraint? the costraint formulation is : w^2/8000 , w:frequency

thanks.

### RE: Defining frequency dependent constraint in Nastran sol 200

Look at the DCONSTR entry. Field 4 (LALLOW/LID) and field 5 (UALLOW/UID) both allow you to reference a constant value (via a real value in field 4/5) or a frequency dependent value defined on TABLED1 entries (via an integer value in field 4/5). You can also restrict the range in which the constraint is active using fields 6/7.

DG

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