Development of an iterative method for structural damage detection and a stochastic model for the random impact series method in modal testing

In this research, NDE methods, including ultrasonic measurement, magnetic particle inspection, penetrant test and visual inspection, were reviewed. A general-order, multiple-parameter perturbation method for eigenvalue problems was developed, which used iteratively with an optimization method such as, generalized inverse, gradient and quasi-Newton method. Numerical simulations on mass-spring system, beam structure and space frame demonstrated the robustness of the algorithm in detecting location and extent of the damage. Moreover, the effects of measurement noise and reduced measurements on performance of the algorithm were evaluated.; A novel stochastic model was developed to describe a random series of impacts in modal testing. The number of the force pulses in a finite time interval was modeled as a Poisson process. The force pulses in the series were assumed to have an arbitrary, deterministic shape function with random amplitudes and arrival times. This model was used to extract modal parameters of the space frame.