/RBODY

Engine Keyword Listed rigid bodies will be activated or deactivated.

Format

/RBODY/Keyword2

node_ID1 … node_IDN

Definitions

Data Description SI Unit Example
Keyword2 Activation flag:
ON
Some part of the previous kinetic energy is accounted for as rotation energy of the rigid body.
OFF
Most of the rotation energy of the rigid body becomes translational kinetic energy.
  
node_ID1 …

node_IDN

 List of main node numbers of rigid bodies.  

Comments

  1. This option can lead to the deactivation of shells and solids entirely connected to a given rigid body, as:
    Activation Flag Effect on Elements Effect on Rigid Bodies
    ON deactivated activated
    OFF activated deactivated
    Default (first run) deactivated activated
    Default (subsequent runs) as previous run as previous run
  2. A limitation with /RBODY/OFF occurs on the solid or thick shell formulation in case a rigid body is set to OFF, and next set ON.

    The stresses in solid elements included into the rigid body are non-zero, but do not turn with the rigid body rotations while the rigid body is set ON.

    Consequently, there will be an error if the rigid body is next set OFF for:
    • 8 node bricks and Isolid =1 or 2
    • 4 node tetrahedra
    • 10 node tetrahedra
    • 16 node thick shells and 20 nodes bricks
  3. The limitation does not apply to:
    • 8 node bricks Isolid = 1 or 2 with Iframe =2
    • 8 node bricks and thick shells type HA8, HEPH and HSEPH
    • 6 node pentahedra PA6
  4. If a rigid body is activated with /RBODY/ON, the center of gravity computation (ICoG) flag is then ignored; the rigid body is activated with respect to ICoG =2 characteristics (/RBODY).