Damage localization from projections of free vibration signals

An approach for damage localization that operates with free vibration signals in the damaged state is presented. The scheme does not directly point to the damage location but, given a postulated distribution, computes a metric that (for ideal conditions) approaches infinity when the distribution is correct. The approach does not use identification, operates without constraints between the number of sensors and the number of model degrees of freedom and differs from model updating in that only the damage distribution (and not the severity) enters the formulation. Analytical and experimental results are included.