ABSTRACT
Vibration-based techniques are increasingly being recognized as effective nondestructive
structural damage identification tools. One promising technique relies on
combining a finite element model (FEM) of the structure under investigation with a set
of experimental frequency response functions (FRFs) to construct a so-called damage
location vector (DLV). Emphasis in this paper is placed on investigating, both
theoretically and experimentally, damage detection using DLVs while attempting to
achieve an enhanced sensitivity through comparisons with baseline measurements of
an initially damaged structure. To this end, the method is first studied theoretically on a
space truss using simulated damage to illustrate its capability. The method is then
improved to handle randomly assigned initial damage that is not predicted by the FEM
through subtraction and normalization of the DLV with respect to baseline data. The
improved method is finally tested experimentally on cantilever beams provided with
damage of various sizes. The proposed technique is effective in identifying damage that
would otherwise be concealed within an initially damaged structure, and provides useful
insight into the location and severity of damage.