Block Format Keyword
/RBODY - Rigid Bodies
Description
Defines rigid bodies.
Format
(1)
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(2)
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(3)
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(4)
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(5)
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(6)
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(7)
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(8)
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(9)
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(10)
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/RBODY/rbody_ID/unit_ID
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rbody_title
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node_ID
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sens_ID
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skew_ID
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Ispher
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Mass
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grnd_ID
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Ikrem
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ICoG
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surf_ID
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JXX
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JYY
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JZZ
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JXY
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JYZ
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JXZ
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Ioptoff
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Field
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Contents
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SI Unit Example
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rbody_ID
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Rigid body identifier
(Integer, maximum 10 digits)
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unit_ID
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Optional unit identifier
(Integer, maximum 10 digits)
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rbody_title
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Rigid body title
(Character, maximum 100 characters)
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node_ID
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Master (primary) node identifier (center of mass)
(Integer)
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sens_ID
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Sensor property identifier (Comment 6)
(Integer)
= 0: no sensor is used
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skew_ID
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Skew identifier
(Integer)
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Ispher
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Spherical inertia flag (Comment 8)
(Integer)
= 0: Inertia is computed from data
= 1: Inertia is set spherical
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Mass
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Mass
(Real)
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grnd_ID
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Slave nodes group identifier
(Integer)
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Ikrem
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Rigid wall deactivation flag
(Integer)
= 0: Remove rigid body slave nodes from rigid wall (default)
= 1: Do not remove rigid body slave nodes from rigid wall
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ICoG
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Center of gravity computation flag (Comments 7 and 8)
Default = 1 (Integer)
= 0: Default, set to 1
= 1: Mass and inertia are added at the master node coordinates; the center of gravity is computed using the master and slave node coordinates, the master node is moved to the computed center of gravity.
= 2: The center of gravity is only computed by taking into account the slave node mass; the master node is moved to the computed center of gravity, added mass and inertia are placed at the center of gravity.
= 3: The center of gravity is set at the master node coordinates; added mass and inertia are placed on the master node coordinates; slave node mass and inertia are transmitted to the center of gravity. The master node is not moved.
= 4: The center of gravity is set at the master node coordinates; added mass and inertia are put on center of gravity. The slave node mass and inertia are ignored. The master node is not moved.
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surf_ID
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Surface identifier defining the envelope surface of the rigid body (optional).
(Integer)
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JXX
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Inertia JXX
(Real)
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JYY
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Inertia JYY
(Real)
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JZZ
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Inertia JZZ
(Real)
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JXY
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Inertia JXY
(Real)
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JYZ
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Inertia JYZ
(Real)
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JXZ
|
Inertia JXZ
(Real)
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Ioptoff
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Manage domain decomposition of rigid body for RADIOSS HMPP flag (Comment 5)
Default = 0 (Integer)
= 0: CPU cost of elements associated with rigid body is not taken into account for domain decomposition load-balancing.
= 1: CPU cost of elements associated with rigid body is taken into account for domain decomposition load-balancing.
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| 1. | Rigid body is set ON by default. All the elements belonging to the rigid body are deactivated in RADIOSS Starter. |
| 2. | If the Ipri flag defined in /IOFLAG has a value greater than or equal to 5, a list of deactivated elements is written in the Starter output file (_0000.out). |
| 3. | This optimization is not done if a rigid body is defined with a sensor (sens_ID ≠ 0), in which case the elements will not be deactivated. |
| 4. | By default the domain decomposition will not take into account the CPU cost of these deactivated elements. |
| 5. | If Ioptoff is set to 1, the domain decomposition will continue to take into account the CPU cost of these elements, as they will be reactivated (worth using for rigid body set OFF in RADIOSS Engine). |
| • | the rigid body is activated and deactivated by the sens_ID; |
| • | the added mass (Mass) and added inertia (Lines 4 and 5) are not used; |
| • | the center of gravity computation (ICoG) flag is ignored; |
| • | the rigid wall deactivation (Ikrem) flag is equal to 1; |
| • | the rigid body is active (not active) when the sensor is not active (respectively, active); |
| • | at the beginning of the simulation (time t=0), the rigid body is activated, as long as the sensor is not active; |
| • | in order to deactivate the rigid body at the beginning of the simulation (from time t=0), use a sensor which is active at time t=0. |
| 7. | If a rigid body is activated into RADIOSS Engine with /RBODY/ON, the center of gravity computation (ICoG) flag is then ignored; the rigid body is activated with respect to ICoG =2 characteristics. |
| 8. | If a rigid body has the same order of size or is smaller than the elements to which it is connected, using Ispher =1 is recommended in order to ensure the stability of the connected elements. |
| 9. | The envelope surface must only contain hyperellipsoids (see /SURF/ELLIPS). |
| 10. | Inertia is given in the skew system reference frame. |
| 11. | By default, the global reference frame is used. |
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See Also:
Implicit Features and Compatibility Information
Skew and Frame (/SKEW & /FRAME)
Kinematic Constraints in ALE and CFD in User's Guide
Incompatible Kinematic Conditions in User's Guide
Mesh node and master node of rigid body in FAQ
Rigid body unstable in FAQ
Master node of rigid body in FAQ
Time step computation for rigid body in FAQ
Rigid Body in Theory Manual
Example 2 - Snap-through Roof
Example 3 - S-beam Crash
Example 10 - Bending
Example 12 - Jumping Bicycle
Example 14.1 - VPG with a Complete Finite Element Model
Example 15 - Gears
Example 17.1 - Densities
Example 22.1 - Ditching using SPH
Example 23 - Brake
Example 24 - Laminating
Example 25 - Spring-back
Example 27 - Football (Soccer) Shots
Example 42 - Rubber Ring: Crush and Slide
Example 48 - Solid Spotweld
Example 49 - Bird Strike on Windshield
