Structural Damage Recognition Based on Perturbations of Curvature Mode Shape and Frequency

A new method for structural damage identification is presented based on perturbations of curvature mode shape and frequency. Firstly, the structure's mass and stiffness matrices are expressed as functions of its elements' physical parameters, which reflect their damage states. According to differences in the curvature mode shape of the structure in undamaged and damaged states, possible damage equations and determined damage equations are established and used to solve for the elements' damage parameters. Then, to ensure the accuracy of the recognition result, a reasonable solution is substituted into a damage-checking equation based on the change of frequency of the damaged structure. Numerical examples are used to show that, to identify the damage, only one order mode needs to be tested. When the degree of damage is low, first-order perturbation equations can be used to recognize the damage with sufficient accuracy. If the extent of the damage is high, second-order perturbation equations can be used to provide more accurate identification results.