# Deck Setup in OptiStruct 5.0 and higher with OptiStruct 3.5 Objectives and Constraints

Setting up an optimization was simpler in OptiStruct 3.5, but it was also very limited. Starting with OptiStruct 5.0, a lot more flexibility has been added to the way objectives and constraints are set up, but the problem setup is more complex.

Although versions of OptiStruct (including and beyond 5.0) will execute OptiStruct 3.5 decks flawlessly, you are urged to create decks using the new optimization format. This section demonstrates how objectives and constraints in OptiStruct 3.5 (such as comp, freq, wcomp, wfreq, and comb) can be set up in OptiStruct 5.0 and higher.

The new optimization capabilities of OptiStruct 5.0 and higher will not be available if the old format is used for the setup of the optimization problem (if matfrac, mini, maxi, ubcon, or lbcon are present in the setup).

## Minimize Compliance for Constrained Mass Fraction

In OptiStruct 3.5, two cards were used to do this kind of optimization: mini, comp and ubcon, 0.3, volume.

`DESOBJ(MIN)`= 1 and ubcon, 0.3, volume is replaced by

`DESGLB`= 101. Three cards (two DRESP1s and one DCONSTR) defining the responses and constraint values referenced in the header are added after the BEGIN BULK statement:

```
$
DESGLB = 101
$
SUBCASE 1
LOAD = 2
SPC = 1
DESOBJ(MIN) = 1
$
BEGIN BULK
$
DRESP1, 1, comp, COMP
DRESP1, 100, massf, MASSFRAC
DCONSTR, 101, 100, , 0.300
$
```

## Minimize Mass for Constrained Displacement

```
$
DESOBJ(MIN) = 1
$
SUBCASE 1
LOAD = 2
SPC = 1
DESSUB = 101
$
BEGIN BULK
$
DRESP1, 1, weight, MASS
$
DRESP1, 100, disp, DISP, , , 7, , 1202
DCONSTR, 101, 100, , 1.4e-6
$
```

## Minimize Weighted Compliance for Constrained Mass

```
$
DESOBJ = 50
DESGLB = 101
$
SUBCASE 1
LOAD = 2
SPC = 1
WEIGHT = 2.0
$
SUBCASE 2
LOAD = 3
SPC = 1
WEIGHT = 1.0
$
BEGIN BULK
$
DRESP1, 50, wcomp, WCOMP
$
DRESP1, 100, weight, MASS
DCONSTR, 101, 100, , 1.560
$
```

## Maximize Frequency for Constrained Volume

```
$
DESGLB = 101
$
SUBCASE 1
METHOD = 2
SPC = 1
DESOBJ(MAX) = 1
$
BEGIN BULK
$
DRESP1, 1, freq1, FREQ, , , 1
$
DRESP1, 100, vol, VOLUME
DCONSTR, 101, 100, , 20000.0
$
```

## Maximize Weighted Frequencies for Constrained Volume

```
$
DESGLB = 101
$
DESOBJ(MIN) = 11
SUBCASE 1
METHOD = 2
SPC = 1
MODEWEIGHT, 1, 1.0
MODEWEIGHT, 2, 1.0
$
BEGIN BULK
$
DRESP1, 11, wfreq, WFREQ
$
DRESP1, 100, vol, VOLUME
DCONSTR, 101, 100, , 20000.0
$
```

## Minimize Combined Compliance and Frequencies for Constrained Volume Fraction

In OptiStruct 3.5, the combined reciprocal frequency and compliance response (comb) required a normalization factor in order to properly add frequency values and compliance. The equivalent setup for OptiStruct 5.0 and higher is shown below.

```
$
DESOBJ(MIN) = 50
DESGLB = 101
$
NORM = 1000.0
$
SUBCASE 1
LOAD = 2
SPC = 1
WEIGHT = 1.0
$
SUBCASE 2
LOAD = 3
SPC = 1
WEIGHT = 1.0
$
SUBCASE 3
METHOD = 10
SPC = 1
MODEWEIGHT, 1, 1.5
MODEWEIGHT, 2, 1.0
$
BEGIN BULK
$
DRESP1, 50, comp, COMB
$
DRESP1, 100, volf, VOLFRAC
DCONSTR, 101, 100, , 0.300
$
```