Detecção de danos em vigas empregando o método das diferenças nas curvaturas modais

Abstract

The presence of damage to the structures may decrease its mechanical strength, reduce its lifetime and cause insecurity to the users. In recent years, the monitoring of structural behavior has gained great importance along with damage assessment and verification of structural safety. The damages may change the dynamic characteristics of structures as natural frequencies, damping ratio and mode shapes. Experimental techniques based on vibrational analysis are used in the detection and location of damage in structures from these changes. In this context, this work aimed to investigate the application of the method based on modal curvatures differences for damage detection in beams from data obtained in dynamic tests. The first three flexural modes of beams in free suspension were used. Variations in modal curvatures were determined approximately by finite differences. The identification of the damage was assessed by comparing the intact beam with a damaged beam. The difference in modal curvatures method has potential to indicate the damage location for different intensities and positions. However good results were obtained just for the cases in which the three modes analyzed have suffered interference of the damage. It is concluded that for achieving good results in localization of damages in beams with the difference in modal curvature method is necessary to conduct the analyzes at least three vibration modes.