An Improved Approach for Damage Identification in Plate-Like Structures Based on Modal Assurance Criterion and Modal Strain Energy Method

The modal strain energy (MSE) method is proven in many research pieces as an effective tool for damage detection in plate-like structures. However, in some complicated damage scenarios, the damage detection results are not accurate. This study presents an improved two-stage approach based on the Modal Assurance Criterion (MAC) and MSE method to boost the efficiency of MSE. Firstly, a new damage indicator named Modal Strain Energy Damage Index (MSEDI), based on MAC, is developed to locate potential damage elements more accurately in the first stage. Then, the damaged zones in plate structures are determined in both locations and extents in the second stage by minimizing an objective function using a genetic algorithm (GA) algorithm. Two different objective functions, global MSE, and local MSE are considered to examine their efficiencies on the performance of the GA algorithm. Finally, the feasibility of the proposed approach is investigated by numerical examples on a plate comprising multiple damage scenarios and different boundary conditions. The obtained results indicate that even in highly complex damage scenarios, the proposed improvement can identify the actual damage sites and estimate the extent of damage with high precision. The numerical results also show that the computational cost of the optimization process using the objective function based on local MSE change is much lower than that using the objective function based on global MSE change.