# ross.Orbit#

class ross.Orbit(*, node, node_pos, ru_e, rv_e)#

Class used to construct orbits for a node in a mode or deflected shape.

The matrix H contains information about the whirl direction, the orbit minor and major axis and the orbit inclination. The matrix is calculated by $$H = T.T^T$$ where the matrix T is constructed using the eigenvector corresponding to the natural frequency of interest:

$\begin{split}\begin{eqnarray} \begin{bmatrix} u(t)\\ v(t) \end{bmatrix} = \mathfrak{R}\Bigg( \begin{bmatrix} r_u e^{j\eta_u}\\ r_v e^{j\eta_v} \end{bmatrix}\Bigg) e^{j\omega_i t} = \begin{bmatrix} r_u cos(\eta_u + \omega_i t)\\ r_v cos(\eta_v + \omega_i t) \end{bmatrix} = {\bf T} \begin{bmatrix} cos(\omega_i t)\\ sin(\omega_i t) \end{bmatrix} \end{eqnarray}\end{split}$

Where $$r_u e^{j\eta_u}$$ e $$r_v e^{j\eta_v}$$ are the elements of the ith eigenvector, corresponding to the node and natural frequency of interest (mode).

$\begin{split}{\bf T} = \begin{bmatrix} r_u cos(\eta_u) & -r_u sin(\eta_u)\\ r_u cos(\eta_u) & -r_v sin(\eta_v) \end{bmatrix}\end{split}$
Parameters
nodeint

Orbit node in the rotor.

ru_ecomplex

Element in the vector corresponding to the x direction.

rv_ecomplex

Element in the vector corresponding to the y direction.

Methods

__init__(*, node, node_pos, ru_e, rv_e)#
calculate_amplitude(angle)#

Calculates the amplitude for a given angle of the orbit.

Parameters
anglefloat, str, pint.Quantity
Returns
amplitude, phasetuple

Tuple with (amplitude, phase) value. The amplitude units are the same as the ru_e and rv_e used to create the orbit.

Load results from a .toml file.

This function will load the simulation results from a .toml file. The file must have all the argumentâ€™s names and values that are needed to reinstantiate the class.

Parameters
filestr, pathlib.Path

The name of the file the results will be loaded from.

Examples

>>> # Example running a stochastic unbalance response
>>> from tempfile import tempdir
>>> from pathlib import Path
>>> import ross as rs
>>> # Running an example
>>> rotor = rs.rotor_example()
>>> freq_range = np.linspace(0, 500, 31)
>>> n = 3
>>> m = 0.01
>>> p = 0.0
>>> results = rotor.run_unbalance_response(n, m, p, freq_range)
>>> # create path for a temporary file
>>> file = Path(tempdir) / 'unb_resp.toml'
>>> results.save(file)
>>> abs(results2.forced_resp).all() == abs(results.forced_resp).all()
True

plot_orbit(fig=None)#

Read and parse data stored in a .toml file.

The data passed to this method needs to be according to the format saved in the .toml file by the .save() method.

Parameters

Returns
The result object.
save(file)#

Save results in a .toml file.

This function will save the simulation results to a .toml file. The file will have all the argumentâ€™s names and values that are needed to reinstantiate the class.

Parameters
filestr, pathlib.Path

The name of the file the results will be saved in.

Examples

>>> # Example running a unbalance response
>>> from tempfile import tempdir
>>> from pathlib import Path
>>> import ross as rs

>>> # Running an example
>>> rotor = rs.rotor_example()
>>> speed = np.linspace(0, 1000, 101)
>>> response = rotor.run_unbalance_response(node=3,
...                                         unbalance_magnitude=0.001,
...                                         unbalance_phase=0.0,
...                                         frequency=speed)

>>> # create path for a temporary file
>>> file = Path(tempdir) / 'unb_resp.toml'
>>> response.save(file)