Damage identification in plates based on the ratio of modal strain energy change and sensitivity analysis

A two-step method based on modal strain energy is presented for damage identification in thin plates. In the first step, damage is localized with the modal strain energy change ratio approach. A method is proposed to weaken the Vicinity Effect', thus reduces the false alarms in the localization of damage. In the second step, the damage extents of the suspected damaged elements are obtained iteratively with modal strain energy change sensitivity-based finite element model updating approach. Model reduction is introduced to eliminate the measurement of rotation degrees-of-freedom in the mode shapes. Two numerical examples are studied to demonstrate the effectiveness and robustness of the proposed method. Both single damage and multiple damage cases are studied and good identification results are obtained. The effect of measurement noise on the identification results is investigated.