A Combined Model-Based Identification and Model Validation Approach for Damage Identification

Robust control techniques have enabled engineers to create uncertain models which are able to describe any differences between the model and actual system with uncertainties in a combination of exogenous inputs and plant perturbations. Model validation techniques arose to provide a guarantee that the uncertain model is able to recreate all experimental data. Such model validation techniques have been successfully applied to structural healthy monitoring, invalidating the healthy model when compared to data taken in the presence of damage. Additionally, the technique of model-based identification, originally created to identify the dynamics resulting from unmodeled or under-modeled components in rotordynamic systems, has been employed to identify the difference in dynamics due to the presence of damage. In previous work, the authors detected and identified the change in dynamics in a rotordynamic test rig due to a change in structure. Later, the authors extended the technique to a local change in dynamics due to an approximated crack in a rotor. In the present work, the approach is extended further to identifying the dynamics due to a breathing crack approximation in a similar rotordynamic test setup, with comparison to simulation. Refinement of the model-based identification technique is conducted to account for any errors between the healthy model and data, allowing for a finer look at the contribution due to the damage. doi: 10.12783/SHM2015/64