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reliability_growth

class reliability.Repairable_systems.reliability_growth(times=None, target_MTBF=None, show_plot=True, print_results=True, log_scale=False, model='Duane', **kwargs)

Fits a reliability growth model to failure data using either the Duane model or the Crow-AMSAA model.

Parameters:

  • times (list, array) – The failure times relative to an initial start time. These are actual failure times measured from the start of the test NOT failure interarrival times.

  • target_MTBF (float, int, optional) – The target MTBF for the reliability growth curve. Default is None.

  • log_scale (bool, optional) – Sets the x and y scales to log scales. Only used if show_plot is True.

  • show_plot (bool, optional) – Default is True. If True the plot will be generated. Use plt.show() to show it.

  • model (str, optional) – The model to use. Must be ‘Duane’ or ‘Crow-AMSAA’. Default is ‘Duane’.

  • print_results (bool, optional) – Default is True. If True the results will be printed to the console.

  • kwargs – Other keyword arguments passed to matplotlib.

Returns:

  • Lambda (float) – The Lambda parameter from the Crow-AMSAA model. Only returned if model=’Crow-AMSAA’.

  • Beta (float) – The Beta parameter from the Crow-AMSAA model. Only returned if model=’Crow-AMSAA’.

  • growth_rate (float) – The growth rate of the Crow-AMSAA model. Growth rate = 1 - Beta. Only returned if model=’Crow-AMSAA’.

  • A (float) – The A parameter from the Duane model. Only returned if model=’Duane’.

  • Alpha (float) – The Alpha parameter from the Duane model. Only returned if model=’Duane’.

  • DMTBF_C (float) – The Demonstrated cumulative MTBF. The is the cumulative MTBF at the final failure time.

  • DMTBF_I (float) – The Demonstrated instantaneous MTBF. The is the instantaneous MTBF at the final failure time.

  • DFI_C (float) – The demonstrated cumulative failure intensity. This is 1/DMTBF_C.

  • DFI_I (float) – The demonstrated instantaneous failure intensity. This is 1/DMTBF_I.

  • time_to_target (float, str) – The time to reach target_MTBF. If target_MTBF is None then time_to_target will be a str asking for the target_MTBF to be specified. This uses the model for cumulative MTBF.

Notes

For more information see the documentation.