The edge of material loss is crucial for material loss evaluation. Lamb wave tomography and model-based edge detecting have been used in isotropic media. Time of flight and velocity of lamb wave are ultrasonic signal features to reconstruct the edge map of material loss. The correlation technique is employed to get the time of arrival more accurate. An ellipse model is used to represent the defects with apparent directional property, and edge detecting will be realized by it. The reconstructed map shows clearly that edge detecting method in this paper is efficient for material loss detection.

The curved structural plate components have been widely used in petroleum, natural gas, chemical industry, and other industries fields, monitoring and detecting the curved structural plate components flaw has a great significance for improving the components integrity, reliability and lifespan in service. Based on the elastic wave fundamental theory, elastic wave equations, and phase velocity dispersion characteristic curves in curved plate component, the article gives the phase velocity practical detecting method. By using thecomsolfinite element software, the author proposed a wave propagating forward modeling analytical method, which gives a guidance to study the relationship between the wave and the flaw. By adopting the ellipse algorithm, the article proposed a positioning and imaging method which was used to locate the flaws position and distinguish the flaws direction. Based on the theoretical and technical analysis above, a number of experiments has been done, and the results shows that the detecting and imaging method can locate and image the flaws position and its geometrical morphology precisely for the curved plates flaw detecting.