Structural identification with unknown input excitation

In this paper, an improved MQRD(Multiple model based on QR Decomposition)-ILS(Iterative Least-Squares) method is proposed to estimate the structural parameters at the element level using response data alone, without using any information on excitation measurements for the assessment of local damages and deterioration in structural systems. The proposed method uses a multiple model least-squares method based on the MQRD for estimating the least-squares parameters. A MQRD-ILS technique that utilizes the assumed structural parameters estimated on the basis of the engineering drawings, visual inspection, field measurements, and/or Nondestructive Test(NDT) is proposed to identify local damages of structural members using measured responses only. In example applications, it has been shown that the improved MQRD-ILS method can precisely identify the structural parameters with high precision in most cases.