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Example 3 - Isotropic Bearings, asymmetrical rotor.ΒΆ

In this example, we use the rotor seen in Example 5.9.1 from [Friswell, 2010]. A 1.5-m-long shaft, with a diameter of \(0.05 m\). The disks are keyed to the shaft at \(0.5\) and \(1 m\) from one end. The left disk is \(0.07 m\) thick with a diameter of \(0.28 m\); the right disk is \(0.07 m\) thick with a diameter of \(0.35 m\). For the shaft, \(E = 211 GN/m^2\) and \(G = 81.2 GN/m^2\). There is no internal shaft damping. For both the shaft and the disks, \(\rho = 7,810 kg/m^3\). The shaft is supported by identical bearings at its ends.

These bearings are isotropic and have a stiffness of \(1 MN/m\) in both the x and y directions. The bearings contribute no additional stiffness to the rotational degrees of freedom and there is no damping or cross-coupling in the bearings.

import ross as rs
import numpy as np
# Classic Instantiation of the rotor
shaft_elements = []
bearing_seal_elements = []
disk_elements = []
steel = rs.Material.load_material("Steel")
for i in range(6):
    shaft_elements.append(rs.ShaftElement(L=0.25, material=steel, n=i, idl=0, odl=0.05))

disk_elements.append(
    rs.DiskElement.from_geometry(n=2, material=steel, width=0.07, i_d=0.05, o_d=0.28)
)

disk_elements.append(
    rs.DiskElement.from_geometry(n=4, material=steel, width=0.07, i_d=0.05, o_d=0.35)
)
bearing_seal_elements.append(rs.BearingElement(n=0, kxx=1e6, kyy=1e6, cxx=0, cyy=0))
bearing_seal_elements.append(rs.BearingElement(n=6, kxx=1e6, kyy=1e6, cxx=0, cyy=0))

rotor591c = rs.Rotor(
    shaft_elements=shaft_elements,
    bearing_elements=bearing_seal_elements,
    disk_elements=disk_elements,
)

rotor591c.plot_rotor()