This paper characterizes laser-generated guided waves in a metal-lined composite-overwrapped pressure vessel (COPV) to assess typical damage, including interfacial debonding and low-velocity impact damage. First, an eigenfrequency approach that avoids additional coding is utilized to theoretically analyze the dispersion characteristics of a COPV. The theoretical results show that interfacial debonding significantly alters dispersion curves, and the wavenumber of the L(0, 1) mode is sensitive to impact damage. Experimental verifications were conducted based on the full wavefield acquired using a scanning laser-ultrasonic system with a repetition rate of 1 kHz. By comparing the experimental dispersion curves with the theoretical ones, it was found that the metal-composite interface was not bonded. In addition, a local wavenumber estimation method was established to detect the impact damage by obtaining the spatial distribution of the wavenumber of the L(0, 1) mode.

Estimation of the elastic properties in composite laminates is very important. Researchers usually consider the laminate as a whole and identify its equivalent stiffness properties. However, determining the elastic properties of each layer within a laminate can provide more comprehensive information to the users. In this paper, an ultrasonic method is proposed to reconstruct the single-ply elastic properties by combing bulk and guided waves. Herein, a novel double-side-transmitted bulk wave method is developed to identify the stacking sequences, providing the necessary information for further evaluation of the single-ply elastic properties. The double-side-transmitted bulk wave method is demonstrated under various layup scenarios, allowing the detection of more layers than conventional techniques. The laser-generated guided wave velocities are then inverted by genetic algorithms (GAs) to reconstruct the single-ply elastic properties. An effective indicator, the coefficient of variation, is designed to represent the accuracy of the identified single-ply material properties. And the experimental dispersion curves are in good agreement with the theoretical dispersion curves under the identified material properties.