AlignedJournalBearing

Model ElementSpecifies a journal bearing that can overtake radial loads.

Class Name

AlignedJournalBearing

Description

The AlignedJournalBearing is a combination of a force element and optionally, a planar or inplane joint. The force element is a function of bearing dimensions, relative radial displacement, and velocity, as well as rotational velocity between the inner journal and outer bearing. The force can act only radially between the inner journal and outer bearing and does not account for tilting and axial misalignment.

The journal bearing is defined by the following dimensions:

Attributes

The table below summarizes the attributes of the AlignedJournalBearing 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 has to 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 where the output results are written.

By default, output_rm is equal to rm.

method Enum(

“sommerfeld_short

sommerfeld_long

gumbel_short

gumbel_long

dynamic_gumbel_short

dynamic_gumbel_long

”)

The methodology (mathematical equation) used to define the hydrodynamic forces.
internal_connection_type Enum(

“NONE

INPLANE

PLANAR”,

Default=”INPLANE”)

The type of joint/jprim used to constrain the journal and the bearing together, so the 2D representation is applied correctly. The bearing methodology only calculates the radial forces between the journal and the bearing.
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.
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.
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 the IMPACT contact element.

Example

jb = AlignedJournalBearing(id=1,
label=AlignedJournalBearing,
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="PLANAR",
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
)