BSBOUNDS (Define Bounding Box for Contact)

Description

The BSBOUNDS entry defines a bounding box in three-dimensional space outside of which contact will not occur. Use of this entry can dramatically reduce the computation times in certain classes of problems.

The BSBOUNDS entry allows you to define a “contact process zone” for all contact surfaces in the model. Any faces of the contact surfaces that are outside these bounds will automatically be rejected for consideration in the contact enforcement.

Consider a metal rolling problem in which a flat work piece of sheet metal is fed into a set of rollers to form some complex shape. All the contact in the problem will occur in a process zone between the rollers. Since we will feed the entire sheet into the rollers and the rollers may perform multiple full revolutions, the contact surfaces in the problem must include the entire perimeter of the rollers and all the faces of the sheet metal (both sides of shell elements for two-sided contact). At any point in the analysis, only a small fraction of the faces are in contact. The faces in contact are the faces in the process zone. The BSBOUNDS entry allows us to drastically reduce the required contact search and tracking computations because we can simply reject any face outside the bounds as a possible contact candidate.

If the bounding box has zero or negative volume, an error will be issued.

Format

Example