Damage Detection In Offshore Jacket Structures From Limited Modal Information

An algorithm to locate and size damage in jacket-type offshore structures for which only post-damage modal parameters are available for few modes of vibration is presented. A theory of damage localization and severity estimation (which yields information on the location and severity of damage directly from changes in mode shapes) is formulated. Next, a method to identify baseline modal parameters (i.e., frequencies, damping, and mode shapes of the undamaged state) of the structures is formulated. Finally, the feasibility of the damage detection algorithm is demonstrated by using a numerical example of an offshore jacket platform with limited modal information.