Input/output system identification of simultaneous mass/stiffness damage assessment using discrete-time pulse responses, differential evolution algorithm, and equivalent virtual damped SDOF

This paper describes a new approach for simultaneous assessment of the extent of massstiffness damages in aerospace structures. Before and after a damage occurrence, we used some system digital pulse response data related to a selected number of collocated sensoractuator DOFs to assess the extent of damage that occurred in a structure. Using method, we can identify an equivalent virtual damped SDOF (EVDSDOF) system through the pulse responses extracted from the instrumented DOFs. After a damage occurrence, monitoring changes, in mass and stiffness properties of a structure, results in identifying the type and size of that damage. The differential evolution algorithm is used as an intelligent optimizer. It performs a curve fitting operation by introducing an EVDSDOF system, replacing the dynamical responses generated by the monitored DOF. Because most of researches for damage assessment identify only the stiffness damages and assume that there is no mass reduction in the in-flight test data of aerospace structures, this new approach can be applied to structures subjected to both mass and stiffness damages. This approach has been verified with some numerical simulations. The algorithm performance is satisfactory. Copyright (c) 2012 John Wiley & Sons, Ltd.