mwdi 0.72

Morlet Wave Damping Identification.

MWDI - Morlet-Wave Damping Identification

This is the Python implementation of the Morlet-Wave damping identification method, see [1] and [2] for details.

This package is based on the MorletDamping code developed by WANG Longqi and was created within the MSCA IF project NOSTRADAMUS.

Simple example

A simple example how to identify damping using MWDI method:

import mwdi as mw
import numpy as np

# set time domain
fs = 5000 # sampling frequency [Hz]
N = 5000 # number of data points of time signal
time = np.arange(N) / fs # time vector

# generate a free response of a SDOF damped mechanical system
w_n = 2*np.pi * 100 # undamped natural frequency
d = 0.01 # damping ratio
x = 1 # amplitude
phi = 0.3 # phase
response = x * np.exp(-d * w_n * time) * np.cos(w_n * np.sqrt(1 - d**2) * time - phi)

# set MWDI object identifier
identifier = mw.MorletWave(free_response=response, fs=fs)

# identify damping
dmp = identifier.identify_damping(w=w_n, root_finding='Newton')
print(dmp)

References

[1]

J. Slavič, M. Boltežar, Damping identification with the Morlet-wave, Mechanical Systems and Signal Processing, 25 (2011) 1632–1645, doi: 10.1016/j.ymssp.2011.01.008.

[2]

I. Tomac, J. Slavič, Damping identification based on a high-speed camera. Mechanical Systems and Signal Processing, 166 (2022) 108485–108497, doi: 10.1016/j.ymssp.2021.108485.