*GEOMETRIC TOLERANCES

Keyword type: step

This option allows the specification of the geometric tolerances in a *ROBUST DESIGN analysis. It can be defined on a node-by-node basis and consists of a mean value and a standard deviation, both in length units. In a robust design analysis random field vectors are generated representing the geometric tolerances up to a specified accuracy.

There is one required parameter TYPE=NORMAL and there is one optional parameter CONSTRAINED. TYPE=NORMAL specifies that the tolerances are normally distributed. Right now, this is the only distribution allowed. The CONSTRAINED parameter enforces a smooth transition between those parts in the structure for which tolerances were defined and the remaining parts.

First line:

• *GEOMETRIC TOLERANCES
• Enter any needed parameters and their value

Second line:

• Node number or node set label.
• Mean value of the tolerance.
• Standard deviation of the tolerance.

Repeat this line if needed.

Example:

*GEOMETRIC TOLERANCES,TYPE=NORMAL,CONSTRAINED
N1,1.5,3.7

assigns normally distributed tolerances with a mean value of 1.5 length units and a standard deviation of 3.7 length units to all nodes in set N1. The random fields are constrained, i.e. a smooth transition of the random field vectors is requested between the nodes in set N1 and the remaining nodes in the structure.

Example files: beamprand.