*GEOMETRIC CONSTRAINT

Keyword type: step

With *GEOMETRIC CONSTRAINT one can define geometric constraints in a feasible direction step. It can only be used for design variables of type COORDINATE.

Right now, the following geometric constraint types are allowed:

• FIXSHRINKAGE: the structure is not allowed to shrink for the given node set:
• FIXGROWTH: the structure is not allowed to grow for the given node set.
• MAXMEMBERSIZE: the minimum distance between each node of a given set and the nodes of an opposite node set is not allowed to exceed a given size in the user's units.
• MINMEMBERSIZE: the minimum distance between each node of a given set and the nodes of an opposite node set is not allowed to fall below a given size in the user's units.

There are now parameters on this keyword.

First line:

• *GEOMETRIC CONSTRAINT.

Second line:

• the type of the geometric constraint
• a node set
• an opposite node set (only for type MAXMEMBERSIZE and MINMEMBERSIZE)
• an absolute value (only for type MAXMEMBERSIZE and MINMEMBERSIZE)

Repeat this line if needed.

Example:

*FEASIBLE DIRECTION
*GEOMETRIC CONSTRAINT
MAXMEMBERSIZE,N1,N2,.1

specifies that the distance between each node of set N1 and the nodes in set N2 should not exceed .1 in the user's units.

Example files: .