Shaped input distributions for structural damage localization

Given a structure in a state with any type of perturbation, the steady-state vibrational response will be identical to that in the unperturbed state if the perturbation is rendered dormant and, of course, if the load distribution is the same in the two states. Guided by this principle, a damage localization method is cast that operates on the premise of shaping inputs-whose spatial distribution is fixed-by use of a model, such that these inputs, in one structural subdomain at a time, suppress certain steady-state vibration quantities (depending on the type of damage one seeks to interrogate for). Accordingly, damage is localized when the vibration signature induced by the shaped inputs in the damaged state corresponds to that in the reference state, hereby implying that the approach does not point directly to damage. Instead, it operates with interrogation based on postulated damage patterns, resulting in a system identification-free procedure whose primary merits, besides avoiding the typical bottleneck of system identification, include a low demand on output sensors, robustness towards noise, and conceptual simplicity. The price paid for these merits is reliance on a relatively accurate model of the structure in its reference state and the need for multiple controllable inputs.