Using Vibration Data and Statistical Measures to Locate Damage in Structures

MI Friswell (University of Wales Swansea), JET Penny & DAL Wilson (Aston University)

Modal Analysis: The International Journal of Analytical and Experimental Modal Analysis, Vol. 9, No. 4, 1994, pp. 239-254

Abstract

Structural damage, such as cracks, usually cause a local reduction in stiffness. Visual inspection may not locate the damage and many papers consider the identification of this stiffness reduction from measured vibration data. Model updating may be used to estimate the stiffness at all the potential damage sites simultaneously, the largest reduction in stiffness giving the most likely damage site. Often model updating will spread the effect of the damage around the structure, making the localisation of the damage difficult. A few earlier papers have assumed that the damage occurs at one position and found the statistically most likely damage location. Their approach is examined in this paper but an alternative statistical method of identification, using generalised least squares theory, is suggested. The method uses the ratio of natural frequencies from both the measured and analytical data. In this way the most likely damage location is identified for a range of damage levels. The different approaches are compared using simulated and experimental data.

Paper Availability

This material has been published in the Modal Analysis: The International Journal of Analytical and Experimental Modal Analysis, Vol. 9, No. 4, 1994, pp. 239-254, the only definitive repository of the content that has been certified and accepted after peer review. Copyright and all rights therein are retained by Society for Experimental Mechanics. The Society for Experimental Mechanics stopped publishing Modal Analysis at the end of 1996. Sage Science Publishers, Thousand Oaks, California, purchased the rights and incorporated Modal Analysis into its existing publication, The Journal of Vibration and Control.


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