/IMPACC
Block Format Keyword Defines imposed accelerations on a group of nodes.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/IMPACC/impacc_ID/unit_ID | |||||||||
impacc_title | |||||||||
fct_IDT | Dir | Skew_ID | sens_ID | grnd_ID | |||||
Ascalex | FscaleY | Tstart | Tstop |
Definition
Field | Contents | SI Unit Example |
---|---|---|
impacc_ID | Imposed acceleration block
identifier. (Integer, maximum 10 digits) |
|
unit_ID | Unit Identifier. (Integer, maximum 10 digits) |
|
impacc_title | Imposed acceleration block
title. (Character, maximum 100 characters) |
|
fct_IDT | Time function
identifier. (Integer) |
|
Dir | Direction: X, Y, and Z in
translation; XX, YY, and ZZ in rotation. (Text) |
|
Skew_ID | Skew
identifier. (Integer) |
|
sens_ID | Sensor identifier.
(Integer) |
|
grnd_ID | Node group on which the
imposed acceleration is applied. (Integer) |
|
Ascalex | Abscissa (time) scale
factor for
fct_IDT. Default = 1.0 (Real) |
|
FscaleY | Ordinate (acceleration)
scale factor for
fct_IDT. Default = 1.0 (Real) |
or |
Tstart | Start
time. (Real) |
|
Tstop | Stop time. Default = 1030 (Real) |
Comments
- The acceleration direction must be right justified in the ten characters of field number 2.
- If Tstart and Tstop are specified, the acceleration is imposed between these times, but the time versus acceleration function is not shifted to begin at Tstart.
- When a sensor is defined sens_ID, the imposed acceleration is applied at the time of sensor activation and the function is shifted by the sensor activation time.
- When a sensor sens_ID is used with Tstart and Tstop, the imposed acceleration will only occur if the sensor activation time occurs between Tstart and Tstop.
- The
AscaleX and
FscaleY are used to scale
the abscissa (time) and ordinate (translational or angular acceleration).The actual load function value is calculated as:
(1) Where, is the function of fct_IDT.
Unlike /GRAV, this keyword is a kinematic condition which is applied to a set of nodes. The node will always be moving with the specified acceleration.