Structural damage detection using inner product vector and low pass filter technique

The inner product vector (IPV) was proposed in our previous research as a damage detection algorithm which uses cross correlation functions between vibration responses under band pass white noise excitation. It was verified that the IPV of a structure is a weighted summation of the mode shapes of the structure and the weighing factors for each modes are different. Structural damage detection examples in our previous research shown that the damage location can be correctly detected if the bandwidth of the band pass white noise excitation only covers the fundamental natural frequency of the structure. However, the bandwidth of the band pass white noise excitation may cover first several natural frequencies of the structure in practice. This paper just investigates the damage detection method using IPV under the situation when the bandwidth of the band pass white noise excitation may cover first several natural frequencies of the structure, i.e. the hybrid method using IPV and low pass filter technique. Firstly, the theory of IPVs and the damage detection method using IPV are reviewed shortly. Then, the hybrid method using IPV and low pass filter technique is introduced. Finally, experimental damage detection example of a shear frame structure is presented to illustrate the method proposed in this paper.