Move Limits for Topology Design

GENESIS structural optimization uses approximated responses so that the optimization problem is solved more efficiently. In general, the approximations are close to the design variable value at which they are constructed. This makes it necessary to limit the range of design variable values for which the approximations are used. These limits are used as temporary bounds in a particular design cycle. At the end of the optimization the move limits should not have affected the results.

For topology design, the move limits include:

• Fractional Topology Move Limit (DELT)

• Minimum Topology Move Limit (DTMIN)

The temporary bounds created using move limits at design cycle i for design variable X are:

Where TMIN is minimum value of topology design variable.

Fractional Topology Move Limit is the fractional change allowed for each topology design variable during the approximate optimization. Default value is 1.0E-6.

Minimum Topology Move Limit (DTMIN) is the minimum move limit fraction imposed for topology design variables at a given design cycle. Default values is 0.2.