Damage detection in structures using a few frequency response measurements

This paper presents methods to identify the locations and severity of damage in structures using frequency response function (FRF) data. Basic methods detect the location and severity of structural damage by minimizing the difference between test and analytic FRFs, which is a type of model updating or optimization method; however, the preferred method proposed in this paper uses only a subset of vectors from the full set of FRFs for a few frequencies and calculates the stiffness matrix and reductions in explicit form. To verify the proposed method, examples for a simple cantilever and a helicopter rotor blade are numerically demonstrated. The proposed method identified the location of damage in these objects, and characterized the damage to a satisfactory level of precision.