Modal strain energy-based identification of damage’s location and severity in plate-like structures

Abstract

In recent years, structural health monitoring (SHM) has faced the challenge of developing advanced and efficient damage identification methods for the solution of problems in engineering. In this paper, a two-stage method using modal strain energy to identify the location and the severity of damage in plate-like structures is presented. The first stage utilizes a modal strain energy equivalence index (MSEEI) to determine the damage’s location. The modal strain energy is calculated by the direct method from the finite element model using the 9-node elements for plate structures. A suitable damage threshold is proposed to reduce the number of variables for the next stage. The second stage employs the genetic algorithm (GA) to minimize the objective function based on the modal strain energy. The objective function has the variables relating to the vector of stiffness reduction level (representing the severity of damage) of the damageable elements, which are the result of the previous stage. The feasibility of the method is verified through an aluminum plate problem with diverse damage scenarios. The results show that the presented method is capable of exactly identifying the location and the severity of damage in plate-like structures.