Gradient enhanced damage sizing for structural health management

A gradient enhanced method is proposed to extracting a probability density function of damage size based on damage image from structural health monitoring for providing comprehensive information about damage size. A three-step procedure is designed to construct a likelihood function about damage size from intensity image, and a gradient function is employed as a prior to obtain a narrow distribution of damage size in the Bayesian framework, providing the empirical probability density function of damage size, from which the probability of damage size larger than critical crack size can be calculated. The proposed method converts an ultrasonic damage imaging result to probability density function of damage size, potential to fill the gap between damage detection and damage prognosis.