Allowing for Support mass and stiffness for Bearings

[robert-varley]

It is possible to connect an additional element to a bearing to represent any supporting structure so the bearing is not actually connected to ground, except via an intermediate element with mass and stiffness defined?

[jguarato]

Hi @robert-varley!

The PointMass class is available in ROSS. I believe you could use it.
Here is an example from the tutorial:

n = 6

shaft_elem = [
    rs.ShaftElement(
        L=0.25,
        idl=0.0,
        odl=0.05,
        material=steel,
        shear_effects=True,
        rotary_inertia=True,
        gyroscopic=True,
    )
    for _ in range(n)
]

disk0 = rs.DiskElement.from_geometry(
    n=2, material=steel, width=0.07, i_d=0.05, o_d=0.28
)
disk1 = rs.DiskElement.from_geometry(
    n=4, material=steel, width=0.07, i_d=0.05, o_d=0.28
)
disks = [disk0, disk1]

stfx = 1e6
stfy = 0.8e6
bearing0 = rs.BearingElement(0, kxx=stfx, kyy=stfy, cxx=0, n_link=7)
bearing1 = rs.BearingElement(6, kxx=stfx, kyy=stfy, cxx=0)
bearing2 = rs.BearingElement(7, kxx=stfx, kyy=stfy, cxx=0)

bearings = [bearing0, bearing1, bearing2]

pm0 = rs.PointMass(n=7, m=30)
pointmass = [pm0]

rotor1 = rs.Rotor(shaft_elem, disks, bearings, pointmass)

🔗 https://ross.readthedocs.io/en/latest/user_guide/tutorial_part_1.html#creating-a-rotor-model

[robert-varley]

Ah, yes, that's extremely helpful, thank you. Appreciate your prompt response.