Bushings
In Adams Driveline the bushings are available as supplied in Adams Car. However, there one special bushing for Adams Driveline that allows you introducing frequency dependent effects in the translational directions.
Adams Driveline FD Bushing
Component Name
ac_f_d_bushing
Description
Defines a frequency dependent bushing. This component is based on a GFORCE element. Frequency dependent data is provided in the FD property file. For the translational directions, the spline stiffness as provided in the property file can be replaced by a linear stiffness multiplied by the displacement transfer function. Direction, transfer function coefficients and linear stiffness are provided in the FD property file. If no frequency dependent data is provided, forces and moments are mapped from splines as defined in the (bushing) property file.
Specification
.ADRIVELINE.attachments.ac_f_d_bushing
FD Bushing
Parameters
Parameter: | Type: | Function: |
|---|
property_file | string variable | name of property file (*.bus) |
FD property_file | string variable | name of the FD property file (*.fdb) |
t_preload_x | real variable | translational preload |
t_preload_y | real variable | translational preload |
t_preload_z | real variable | translational preload |
r_preload_x | real variable | rotational preload |
r_preload_y | real variable | rotational preload |
r_preload_z | real variable | rotational preload |
t_offset_x | real variable | translational offset |
t_offset_y | real variable | translational offset |
t_offset_z | real variable | translational offset |
r_offset_x | real variable | rotational offset |
r_offset_y | real variable | rotational offset |
r_offset_z | real variable | rotational offset |
i_geoMarker | marker | geometry ref marker |
j_geoMarker | marker | geometry ref marker |
geoRadius | real variable | geometry radius |
geoLength | real variable | geometry length |
Request Definition
disp_request
Component name: | Component units: | Definition: |
|---|
dx | length | x-distance between i_marker and j_marker |
dy | length | y-distance between i_marker and j_marker |
dz | length | z-distance between i_marker and j_marker |
dm | length | magnitude |
ax | angle | angle about x |
ay | angle | angle about y |
az | angle | angle about z |
amag | angle | magnitude |
velo_request
Component name: | Component units: | Definition: |
|---|
vx | velocity | x-velocity between i_marker and j_marker |
vy | velocity | y-velocity between i_marker and j_marker |
vz | velocity | z-velocity between i_marker and j_marker |
vm | velocity | magnitude |
wx | angular_velocity | |
wy | angular_velocity | |
wz | angular_velocity | |
wm | angular_velocity | magnitude |
force_request
Component name: | Component units: | Definition: |
|---|
fx | force | x-force between i_marker and j_marker |
fy | force | y-force between i_marker and j_marker |
fz | force | z-force between i_marker and j_marker |
fm | force | magnitude |
tx | torque | |
ty | torque | |
tz | torque | |
tm | torque | magnitude |
Calculation of the FD Bushing Force
For the FD Bushing two property files are required:
■A property file for the FD bushing.
In the FD bushing, the DIRECTION keyword in the [MODEL] specifies the directions in which the FD properties have to be applied. The directions that can be specified are: 'x', or 'y', or 'z', or 'xyz'.
The properties of the 'standard' bushing will be
replaced by the properties of the FD bushing for the direction specified. The FD bushing exists of a TFSISO element (see
Transfer Function, Single-Input, Single-Output) multiplied by a stiffness:
FD_force = preload-TFSISO_ouput(deflection+offset)*linear stiffness
For each direction following parameters can be specified:
NUM_NUMBER = N | with N the number of numerators of the TFSISO |
DEN_NUMBER = K | with K the number of denominators of the TFSISO |
NUM_1 = value | specifying the value for the 1-st numerator |
NUM_2 = ... | |
... | |
NUM_N = ... | specifying the value for the n-th numerator |
DEN_1 = value | specifying the value for the 1-st denominator |
DEN_2 = … | |
… | |
DEN_K = … | specifying the value for the k-th denominator |
| |
LINEAR_STIFFNESS = 1 | specifies the linear stiffness of the bushing in this direction |
See below an example of a FD bushing property file:
$-----------------------------------------------------------------MDI_HEADER
[MDI_HEADER]
FILE_TYPE = 'fdb'
FILE_VERSION = 1.0
FILE_FORMAT = 'ASCII'
$----------------------------------------------------------------------UNITS
[UNITS]
LENGTH = 'mm'
ANGLE = 'radians'
FORCE = 'newton'
MASS = 'kg'
TIME = 'second'
$----------------------------------------------------------------------MODEL
[MODEL]
DIRECTION = 'XYZ'
$----------------------------------------------------------------X_DIRECTION
[X_DIRECTION]
NUM_NUMBER = 4
DEN_NUMBER = 4
NUM_1 = 1
NUM_2 = 1
NUM_3 = 1
NUM_4 = 1
DEN_1 = 1
DEN_2 = 1
DEN_3 = 1
DEN_4 = 1
LINEAR_STIFFNESS = 1
$----------------------------------------------------------------Y_DIRECTION
[Y_DIRECTION]
NUM_NUMBER = 4
DEN_NUMBER = 4
NUM_1 = 1
NUM_2 = 1
NUM_3 = 1
NUM_4 = 1
DEN_1 = 1
DEN_2 = 1
DEN_3 = 1
DEN_4 = 1
LINEAR_STIFFNESS = 1
$----------------------------------------------------------------Z_DIRECTION
[Z_DIRECTION]
NUM_NUMBER = 4
DEN_NUMBER = 4
NUM_1 = 1
NUM_2 = 1
NUM_3 = 1
NUM_4 = 1
DEN_1 = 1
DEN_2 = 1
DEN_3 = 1
DEN_4 = 1
LINEAR_STIFFNESS = 1