Structural damage identification using modal strain energy method

Abstract

Civil Engineering structures are prone to deterioration and damage during their service life period. Structural health monitoring is gaining high importance in conjunction with damage assessment and safety evaluation of structures. Vibration based damage identification techniques are global methods that are able to assess the condition of the entire structure at once. In this paper, the damage detection potential of two damage indices based on modal strain energy are evaluated for beam structures under different damage scenarios with respect to locations, severities and single and multiple damages. The appropriate finite element models of beam structures are developed and analysed for first five flexural modes using commercial software ANSYS. The algorithms available in the literature use flexural mode shapes for calculation of damage indices. In the present study, normalized mode shapes as well as normalized curvature mode shapes are used for computation of damage indices. The numerical results demonstrate that the indices could successfully detect and locate the damages in the beam models. In addition, there is improvement in the performance of damage indices in terms of reduction in presence of false alarms.