ross.Rubbing

ross.Rubbing#

class ross.Rubbing(rotor, n, distance, contact_stiffness, contact_damping, friction_coeff, torque=False)#

Model rubbing based on Finite Element Method on a given shaft element of a rotor system.

Contains a rubbing model [Yamamoto et al., 2002]. The reference coordenate system is:

  • x-axis and y-axis in the sensors’ planes;

  • z-axis throught the shaft center.

Parameters:
rotorross.Rotor

Rotor object.

nint

Number of shaft element where rubbing is ocurring.

distancefloat, pint.Quantity

Distance between the housing and shaft surface.

contact_stiffnessfloat, pint.Quantity

Contact stiffness.

contact_dampingfloat, pint.Quantity

Contact damping.

friction_coefffloat

Friction coefficient.

torquebool, optional

If True a torque is considered by rubbing. Default is False.

Attributes:
shaft_elemross.ShaftElement

A 6 degrees of freedom shaft element object where rubbing is ocurring.

forcesnp.ndarray

Force matrix due to rubbing. Each row corresponds to a dof and each column to a time.

Returns:
A rubbing object.

References

[YIK02]

T Yamamoto, Y Ishida, and RG Kirk. Linear and nonlinear rotordynamics: a modern treatment with applications. Applied Mechanics Reviews, 55(3):B45–B46, 06 2002. doi:https://doi.org/10.1115/1.1470671.

Examples

>>> rotor = rs.rotor_example_with_damping()
>>> fault = Rubbing(
...     rotor,
...     n=12,
...     distance=7.95e-5,
...     contact_stiffness=1.1e6,
...     contact_damping=40,
...     friction_coeff=0.3
... )
>>> fault.shaft_elem
ShaftElement(L=0.01, idl=0.0, idr=0.0, odl=0.019,  odr=0.019, material='Steel', n=12)

Methods

__init__(rotor, n, distance, contact_stiffness, contact_damping, friction_coeff, torque=False)#
compute_rubbing_force(y, ydot, ang_speed)#

Calculate the force on the shaft element with rubbing.

Parameters:
ynp.ndarray

Displacement response of the element.

ydotnp.ndarray

Velocity response of the element.

ang_speedfloat

Angular speed of the element.

Returns:
Fnp.ndarray

Force matrix of the element due to rubbing.

run(node, unb_magnitude, unb_phase, speed, t, **kwargs)#

Run analysis for the system with rubbing given an unbalance force.

System time response is simulated.

Parameters:
nodelist, int

Node where the unbalance is applied.

unb_magnitudelist, float

Unbalance magnitude (kg.m).

unb_phaselist, float

Unbalance phase (rad).

speedfloat or array_like, pint.Quantity

Rotor speed.

tarray

Time array.

**kwargsoptional

Additional keyword arguments can be passed to define the parameters of the Newmark method if it is used (e.g. gamma, beta, tol, …). See ross.utils.newmark for more details. Other keyword arguments can also be passed to be used in numerical integration (e.g. num_modes). See Rotor.integrate_system for more details.

Returns:
resultsross.TimeResponseResults

For more information on attributes and methods available see: ross.TimeResponseResults

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