8.8. Contact with Analytic Objects

Contact with analytic objects is desired if a user would like to enforce contact on their meshed body but not modify the mesh file to create the object to come into contact with. This object can be created with the below syntax:

BEGIN ANALYTIC OBJECT <string>analytic_object_name
  TYPE = <string> PLANE
  NORMAL DIRECTION = <real>x_dir <real>y_dir <real>z_dir
  ORIGIN = <real>x <real>y <real>z
  SCALE FACTOR = <real> scale_factor
END [ANALYTIC OBJECT]

This syntax should be placed in the REGION command scope.

When using an analytic object, it is required to give your analytic object a name. This name is then used when specifying contact surfaces. For example, if you were to name your analytic object analytic_obj1, you would specify the contact surface:

CONTACT SURFACE c1 CONTAINS analytic_obj1

The rest of the contact definition is defined using the usual commands. See Section 8.3 for details.

The input command TYPE specifies the type of analytic object to create. Currently the only option is to create an analytic plane.

The input command NORMAL DIRECTION specifies the normal direction of the plane to be created.

The input command ORIGIN specifies the origin at which the plane is created.

By default, the plane that is created is 3X the size of the maximum length of the meshed body. If it is desired to make the plane a different size, the input command SCALE FACTOR can be used to scale the size of the plane.

8.8.1. Kinematic BCs with Analytic Objects

A kinematic boundary condition (such as fixed displacement, prescribed displacement, etc.) can be applied to the analytic object that is created. Within the boundary condition definition, the block name or surface name should be the name given to the analytic object.

If no kinematic BC is defined on the analytic object, a fixed displacement BC will be applied by default.

Other boundary conditions such as pressure, gravity, or force will not function on analytic planes.