TY - JOUR A1 - Döhler, Michael A1 - Mevel, L. A1 - Hille, Falk T1 - Subspace-based damage detection under changes in the ambient excitation statistics T2 - Mechanical systems and signal processing N2 - In the last ten years, monitoring the integrity of the civil infrastructure has been an active research topic, including in connected areas as automatic control. It is common practice to perform damage detection by detecting changes in the modal parameters between a reference state and the current (possibly damaged) state from measured vibration data. Subspace methods enjoy some popularity in structural engineering, where large model orders have to be considered. In the context of detecting changes in the structural properties and the modal parameters linked to them, a subspace-based fault detection residual has been recently proposed and applied successfully, where the estimation of the modal parameters in the possibly damaged state is avoided. However, most works assume that the unmeasured ambient excitation properties during measurements of the structure in the reference and possibly damaged condition stay constant, which is hardly satisfied by any application. This paper addresses the problem of robustness of such fault detection methods. It is explained why current algorithms from literature fail when the excitation covariance changes and how they can be modified. Then, an efficient and fast subspace-based damage detection test is derived that is robust to changes in the excitation covariance but also to numerical instabilities that can arise easily in the computations. Three numerical applications show the efficiency of the new approach to better detect and separate different levels of damage even using a relatively low sample length. PB - Elsevier Ltd. CY - London KW - Damage detection KW - Structural vibration monitoring KW - Ambient excitation KW - Subspace methods KW - Hypothesis testing PY - 2014 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/29899 AN - OPUS4-29899 SN - 0888-3270 VL - 45 IS - 1 SP - 207 EP - 224 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany