| The purpose of this work is to develop a new method to identify damage in a local region of a structure. The inverse system is introduced and related to the forward (ordinary) system, and also to the Remote Sensing System, which offers a means to experimentally identify the transmission zeros of a structure. A new method to extract the Remote Sensing System frequency response function efficiently from experimental data is presented.; Transmission zeros are shown to be modal frequencies of the inverse system, and appropriate choices of sensor locations lead to localized inverse system mode shapes. The localization of inverse system modes results in increased sensitivity to local structural changes, as well as enabling a reduction in the size of the analysis model. Simulations were used to illustrate the application of the identification technique to a simple spring-mass model, and to demonstrate the identification of local mode shapes for a 3-D finite element model. Analysis of the spring-mass models demonstrated that the sensitivity of transmission zeros associated with localized mode shapes can be much greater than that of global mode shapes, and that as the structure increases in size relative to the region of interest, the comparative advantage of the inverse system approach increases. |
