Experimental Investigations and Critical Observations On The Use of Modal Parameters For Structural Damage

Abstract

The global nature of the dynamic properties hasattracted much attention in the structural damage detectionfrom the changes in modal parameters of a structure. Thepopularity behind the use of natural frequencies and modeshapes as damage indicators is that they are easy to interpretphysically. However, both the frequency-based and modeshape-based damage identification methods have their own setof advantages and limitations. This paper examines naturalfrequency as the diagnostic parameter in single and doublecrack situations for a cantilever beam using experimental data.It is shown that the sensitivity of natural frequency to theseverity of damage is dependent on the location of crack. It isalso shown that the changes in frequency follow a nonlinearrelation with the crack depth combinations for the doublecrack situation. Finally, it incorporates some criticalobservations on the vibration-based damage detectiontechniques