title: Reference-free damage detection, localization, and quantification in composites.
abstract: In this study, a reference-free damage characterization technique is developed not only to identify but also to locate and quantify damage in composite structures subject to varying temperature conditions. First, damage is characterized in terms of a damage index (m-value) defined as the ratio of damage size to the wavelength of the A0 mode within the damage. Then, a feasible solution space defining all possible combinations of the damage location and size are estimated without using any prior baseline data obtained from the pristine condition of a structure or different paths. When additional information such as the A0 mode group velocity within the pristine region of the structure becomes available, the estimates for the damage location and size are updated with better accuracy. The uniqueness of this study lies in that damage localization and quantification as well as identification are all performed without comparing current Lamb wave signals with the ones obtained from the pristine condition of the target structure, making the proposed technique more attractive for online monitoring. Numerical and experimental tests are presented to demonstrate the effectiveness of the proposed damage detection technique under varying temperature.
authors.affiliation: Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-Ro, Daejeon, 305-701, South Korea.
authors.forename: Hyung Jin
authors.initials: HJ
authors.lastname: Lim
authors.forename: Hoon
authors.initials: H
authors.lastname: Sohn
authors.forename: Chul Min
authors.initials: CM
authors.lastname: Yeum
authors.forename: Ji Min
authors.initials: JM
authors.lastname: Kim