Structural damage detection from modal strain energy change

A structural damage detection method based on modal strain energy (MSE) cha nge before and after damage is presented in this paper. The localization of damage based on MSE of each structural element is briefly presented, and t he sensitivity of the MSE with respect to a damage is derived. The sensitiv ity is not based on any series expansion and is a function of the analytica l mode shape changes and the stiffness matrix. Only incomplete measured mod e shapes and analytical system matrices are required in this damage localiz ation and quantification approach. Results from a numerical example and an experiment on a single-bay, two-story portal steel frame structure are inve stigated. The effects of measurement noise and truncated analytical mode sh apes are discussed. Results indicate that the proposed approach is noise se nsitive, but it can localize single and multiple damages. Damage quantifica tion of two damages is successful with a maximum of 14% error under a 5% me asurement noise.