Damage Location in Structures Using Vibration Data and Its Sensitivity to Measurement Errors

The presence of a chmage. such a9 a crack, in a ~trwture increases the jlaibility and damping in the structure. To identify changes of thefleribility, vibration mode shapes and natural frequencies are usually used. In this paper. a procedure for damage location in structures using vibration data is described. lbe effectiveness and sensitivity of the presented method to meawrement errors in mode shapes and natural frequencies are investigated using analytical results from finite element modeLF and aperimental data from simple beam wwt~res. It i.s shown thot the errors in the first mode shape andfirst noturalfiequency demoxwate much larger influence than those in the higher mode shapes and modal frequencies. NOMENCLATURE [Ml: Mass matrix [IQ Stiffhess matrix {t-j: Force vector [+I: Mass normalized mode shapes [A]: Flexibility matrix [A,]: Flexibility matrix for the undamaged Structure [A,]: Flexibility matrix for the damaged structure AA,: The change of nodal displacements corresponding to a unit force at the ith degree of freedom