Example 21 - Features of Eigenvalues and Eigenvectors - Hydrodynamic Bearings¶
This example is based on Example 5.9.6 from [Friswell, 2010].
Example 7 from the documentation uses the
BearingFluidFlow class to create a hydrodynamic bearing.
Here we are going to use the
CylindricalBearing class, which is implemented based on [Friswell, 2010].
Hydrodynamic Bearings. Repeat the analysis of Example 5.9.1 when the bearings are replaced with hydrodynamic bearings. The oil-film bear ings have a diameter of 100 mm, are 30 mm long, and each supports a static load of 525 N, which represents half of the weight of the rotor. The radial clearance in the bearings is 0.1 mm and the oil film has a viscosity of 0.1 Pa s. These bearings have the same characteristics as Example 5.5.1.
import ross as rs import numpy as np import plotly.graph_objects as go from IPython.display import display
Q_ = rs.Q_
steel = rs.Material("steel", E=211e9, G_s=81.2e9, rho=7810)
L = 0.25 N = 6 idl = 0 odl = 0.05 shaft = [rs.ShaftElement(L=L, idl=idl, odl=odl, material=steel) for i in range(N)] bearings = [ rs.CylindricalBearing( n=0, speed=Q_(list(range(0, 5000, 50)), "RPM"), weight=525, bearing_length=Q_(30, "mm"), journal_diameter=Q_(100, "mm"), radial_clearance=Q_(0.1, "mm"), oil_viscosity=0.1, ), rs.CylindricalBearing( n=len(shaft), speed=Q_(list(range(0, 5000, 50)), "RPM"), weight=525, bearing_length=Q_(30, "mm"), journal_diameter=Q_(100, "mm"), radial_clearance=Q_(0.1, "mm"), oil_viscosity=0.1, ), ] disks = [ rs.DiskElement.from_geometry( n=2, material=steel, width=0.07, i_d=odl, o_d=0.28, scale_factor="mass" ), rs.DiskElement.from_geometry( n=4, material=steel, width=0.07, i_d=odl, o_d=0.35, scale_factor="mass" ), ] rotor = rs.Rotor(shaft_elements=shaft, disk_elements=disks, bearing_elements=bearings) rotor.plot_rotor()