Damage detection using successive parameter subset selections and multiple modal residuals

• Successive use of the homogeneous modal residuals in damage detection.
• Symmetries, large changes in residuals and multiple damage levels are considered.
• 3D frame structure with a loose joint is used to demonstrate the concept.
• Frequency residuals and symmetries determine the candidate damage regions.
• Mode shape residuals assist selection of one location from the candidate regions.

The use of modal response residuals and parameterized models forms the framework for parameter subset selection based damage detection. This research explores the novel approach in this class of methods which is characterized by the successive application of the homogeneous modal response residuals. The motivation behind this approach is to restrict the use of unknown weighting factors which are employed in cases with mixed response residuals. Particular attention is given to the parameter-effect symmetry issues and large nonlinear changes in response residuals due to increasing damage observed across multiple damage levels. A case study involving a real aluminum three-dimensional frame structure with a loose joint connection is used to demonstrate the approach and its ability to localize the damaged area.