Discussion on sensitivity enhancement methods with different subspace projection methods

The response sensitivity is affected by the measurement noise, and a sensitivity enhancement method has been developed based on subspac projection method. In the decomposition of each measured response of the structure, the trend componets from singular spectrum analysis (SSA) may contain most of the structural information and less noise information. So the trend components of the measured acceleration responses are chosen to construct the subspace for the projection of the sensitivity enquation, and the projected identification equations are then used to detect local damages in the structure. For a structural system with known excitations, the computed response from the original model is noise free, and the trend components of these computed responses are selected to construct the subspace for the projection of the sensitivy equation. These two sensitivity enhancement methods with two kinds of different subspace projection methods are discussed and compared in this paper.