Defining Decision Variables

To optimize these variables with OptQuest, a set of decision variables are defined in cells C20, C21, E18, E19, H18, and H19 (Figure 182, Table of Flow Rate with Cells Defined as Decision Variables).

Figure 182. Table of Flow Rate with Cells Defined as Decision Variables

This figure displays a table showing the flow rate with cells defined as decision variables.

  To view the contents of each decision variable, reset Crystal Ball and:

  1. Select a decision variable cell.

  2. Choose Define, then Define Decision. Define Decision button

  3. In the Define Decision Variable dialog, there is a name, an upper and lower bound, a type setting, and a step size for discrete variables.

    Note:

    If you changed the Piston Radius standard deviation Initial Value and Upper Limit for the last part of the DFSS Pump tutorial, be sure to change them both back to their original values as shown in Figure 182, Table of Flow Rate with Cells Defined as Decision Variables. Also, be sure that these values are included in the decision variable for the Piston Radius standard deviation (Cell H18). Check it as described in steps 1 and 2.

    The upper and lower bound for piston machining variables are the same as those in the Lower Limit and Upper Limit tables of Figure 182, Table of Flow Rate with Cells Defined as Decision Variables. For the motor speed and backflow valve variables, the upper and lower bounds are the lowest and highest options (1 and 9, respectively).

In choosing the piston machining values shown in Figure 182, Table of Flow Rate with Cells Defined as Decision Variables, you could identify raw stock availability to define a range of piston radii and lengths for investigation. You could also identify a feasible range of tolerances for machining the radius and length.