Structural Damage Identification in a Mechanically Attached Metallic Panel Using Embedded Sensitivity Functions

Abstract

A vibration-based structural damage identification method is discussed using experimental embedded sensitivity functions, which are algebraic combinations of measured frequency response functions (FRFs) that reflect changes in the response of mechanical systems when mass, damping, or stiffness parameters are changed. The theory of embedded sensitivity functions is reviewed and applied to identify damage in simulations with a six degree-of-freedom model of a metallic panel and in experiments on the actual panel. Measured FRFs, before and after simulated damage is imposed, are compared to an experimental sensitivity function. By matching the spectral shapes of these two sets of functions, damage is first located and classified as changes in stiffness, damping, or mass. Then the damage is quantified directly in engineering units as changes in stiffness or mass using only the measured data.