/GRAV
Block Format Keyword Defines gravity load on node group.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/GRAV/grav_ID/unit_ID | |||||||||
grav_title | |||||||||
fct_IDT | Dir | skew_ID | sens_ID | grnd_ID | Ascalex | FscaleY |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
grav_ID | Gravity load block
identifier (Integer, maximum 10 digits) |
|
unit_ID | Unit Identifier (Integer, maximum 10 digits) |
|
grav_title | Gravity load block
title. (Character, maximum 100 characters) |
|
fct_IDT | Time function
identifier. (Integer) |
|
Dir | Direction in translation
(input should be: X, Y or Z). (Text) |
|
skew_ID | Skew
identifier. (Integer) |
|
sens_ID | Sensor identifier.
(Integer) |
|
grnd_ID | Node group to which the
gravity load is applied. (Integer) |
|
Ascalex | Abscissa (time) scale
factor. Default = 1.0 (Real) |
|
FscaleY | Ordinate (force) scale
factor. Default = 1.0 (Real) |
Example
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for load
# MUNIT LUNIT TUNIT
g mm ms
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/INIGRAV/1/1
hydrostatique pressure – sea level : {Z=0} where Pref=0.101325 MPa
#GRPART_ID SURF_ID GRAV_ID
0 0 1
# Pref Bx By Bz
0.101325 0 0 0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/GRAV/1/1
Terrestrial gravity field
#funct_IDT DIR skew_ID sensor_ID grnod_ID Ascale_x Fscale_Y
2 Z 0 0 5 0 -0.00981
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/2
unity
# X Y
0 1.0
1000000 1.0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
Comments
- The gravity load direction must be right justified in the ten characters of field number 2.
- The gravity loads are only applied to the nodes defined in grnd_ID, which must not be null.
- The actual load function value is
calculated as follows:
(1) Where,- The function of fct_IDT
/GRAV applies to each node and is stated as force:(2) With m being the mass of node. The node will be moving until a force balance reached.
- If the gravity card is referenced by an /INIGRAV card for Hydrostatic pressure initialization in a Fluid-Structure Interaction simulation, then, fct_IDT must be a constant function from t=0.