6-DOF Bodies Reference

6-DOF Bodies Right-Click Actions

DFBI > 6-DOF Bodies

New Body
Adds a 6-DOF body (2D or 3D, Continuum Body or Mechanical Body—as selected) to the 6-DOF Bodies node.

6-DOF Body Properties

DFBI > 6-DOF Bodies > [6-DOF body]

Body Surface (Continuum Body)
Specifies the boundaries that represent the surface of the body. Opens the in-place part selector for editing (integration of shear force and pressure is over the body surface):
  • Select the wall boundaries that compose the body surface.
  • If the inside of the 6-DOF body is modeled using a solid region, select the fluid side boundaries and the corresponding boundaries for the interface between the fluid and the solid region. The associated interfaces can be of type contact or mapped.
Body Parts (Mechanical Body)
Specifies the body parts that represent the geometry of the body. Opens the in-place part selector for editing. The motion of the mechanical body can be visualized through a DFBI displayer.
Body Mass
Defines mass of the object. For a 2D body, it is interpreted as the value for one unit length of the body in z-direction (in 2D, planar coordinates) or for one unit radian (in axisymmetric coordinates).
Release Time
Specifies time before calculation of body motion begins. It is best to allow some time for the fluid flow to initialize. The number of seconds depends on the time model you are using and the mesh size. In an unsteady model, the typical range would be 10 to 50 time-steps. If a time-step size is equivalent to 0.01 seconds, 50 time-steps would amount to 0.5 seconds.
For Body Motion Option Planar Motion Carriage, the Release Time only applies to the unprescribed degrees of freedom. The prescribed trajectory starts from the very beginning of the simulation without considering the release time. See also: 平面运动载体.
Ramp Time
Facilitates a more robust solution by reducing oscillation. At release time, force and moments are applied to the body and can cause a shock effect. Applying a ramp time applies the forces and moments proportionally across the interval to reduce the shock effect. The value of this property is typically 10 times the release time.
Body Motion Option
Selects the type of body motion from a drop-down list. Free Motion is the default motion type.

For a 3D body, you have the following available options:

For a 2D body, you have the following available options:

Three Dimensional
(Read-only) Indicates if the body is three-dimensional or two-dimensional. For a 2D body, this option is deactivated by default.
Index
(Read-only) Displays a unique number to identify the body.

6-DOF Body Right-Click Actions

DFBI > 6-DOF Bodies > [6-DOF body]

Create
Creates one of the following 6-DOF body related motions:
Body Motion
Outputs the transient 6-DOF body motion to be used somewhere else in the simulation. This option adds a body-drive motion [6-DOF body]-Motion under the Tools > Motions node, where you can superpose other motions to the body-driven motion to be used in other regions.

Unavailable when a body-driven motion already exists for that body.

Follow Motion
Outputs the transient 6-DOF body motion to be used somewhere else in the simulation. This option adds a body-follow motion [6-DOF body]-Follow-Motion under the Tools > Motions node, where you can choose to follow one or more components of the 6-DOF body motion. No further superposed motion can be added to the body-follow motion.

You can add as many body-follow motion as the simulation requires. See also: Follow Motion Reference.

Import Inertial Properties

When simulating flexible DFBI bodies by coupling DFBI and solid stress, the inertial properties of the body on the DFBI side must match the inertial properties of the solid region on the solid stress side.

This option automatically populates the following inertial properties of the 6-DOF body according to the values that are determined on the solid stress side:

  • Body Mass (6-DOF Body Properties)
  • Centre of Mass (6-DOF Body Initial Values)
  • Moment of Inertia (6-DOF Body Initial Values)

Only available for fully deformable DFBI continuum bodies with solid stress.