MisalignedJournalBearing
Model ElementSpecifies a journal bearing that can overtake radial loads and misaligned moments.
Class Name
MisalignedJournalBearing
Description
The MisalignedJournalBearing is a combination of a force element and optionally, an inplane joint. The force element is a function of bearing dimensions, relative radial, and angular displacement and the velocity between the inner journal and outer bearing. The force element applies radial forces and alignment moments between the inner journal and outer bearing. It does not account for axial misalignment.
Figure 1.
Attributes
The table below summarizes the attributes of the MisalignedJournalBearing classes.
| Variable | Type | Notes | Symbol |
|---|---|---|---|
| id | Int() | Unique identification number. | |
| label | Str() | Descriptor of the journal bearing element. | |
| rm | Reference("Marker", required=True) | Reference marker for the journal bearing element. Forces and states are calculated with respect to this marker. The z-axis of the marker must be parallel to the journal bearing’s axial axis. The marker must be attached to the gearbox housing. | |
| mu | Double(required=True) | The dynamic viscosity of the lubricant. | |
| width | Double(required=True) | The width of the journal bearing. | l |
| rj | Double(required=True) | The radius of the journal (inner cylinder). | RJ |
| rb | Double(required=True) | The radius of the bearing (outer cylinder). | RB |
| journal | Reference(“Part", required=True) | The part that acts as the journal. | |
| bearing | Reference(“Part", required=True) | The part that acts as the bearing. | |
| output_rm | Reference("Marker") | Defines the reference marker in which the output results are
written. By default, output_rm is equal to rm. |
|
| method | Enum( “sommerfeld_short gumbel_short ” ) |
The methodology (mathematical equation) used to define the hydrodynamic forces. | |
| internal_connection_type | Enum( “NONE INPLANE”, Default=”INPLANE”) |
The type of joint/jprim used to constrain the journal and the bearing together. | |
| lubrication_force_graphics | Bool(False) | A Boolean flag that creates 3D lubrication force vectors at discrete points around the journal circumference. | |
| force_graphics_scale | Double(1) | A scaling factor for the visualization of lubrication forces. | |
| nr | Int(20) | The number of radial steps along the journal circumference used for the lubrication force vectors, the Max/Min Pressure, and the Min Oil Film Thickness requests, as well as the calculation of lubrication forces and moments. | |
| na | Int(7) | The number of axial steps along the journal axis used for the lubrication force vectors, the Max/Min Pressure, and the Min Oil Film Thickness requests, as well as the calculation of lubrication forces and moments. | |
| contact | Bool(True) | A Boolean flag that enables the IMPACT Contact element between the journal and bearing cylinder graphics. | |
| stiffness | Double(1000) | Stiffness property of the IMPACT Contact element. | |
| damping | Double(0.1) | Damping property of the IMPACT Contact element. | |
| exponent | Double(2.1) | Exponent property of the IMPACT Contact element. | |
| dmax | Double(0.1) | dmax property of IMPACT Contact element. |
Example
jb = MisalignedJournalBearing(id=1,
label="Misaligned Journal Bearing",
rm=reference_marker,
mu=0.05 * 1e-6,
width=40,
rj=9.8,
rb=10,
journal=journal_part,
bearing=bearing_part,
output_rm=reference_marker,
method="gumbel_short",
internal_connection_type="INPLANE",
lubrication_force_graphics=True,
force_graphics_scale=10,
nr=20,
na=7,
contact=True,
stiffness=1000,
damping=0.1,
exponent=2.1,
dmax=0.1
)