Measuring Lamb wave dispersion curves of a bi-layered plate and itsapplication on material characterization of coating

摘要

This paper investigates the Lamb wave dispersion curves of anbi-layered plate and evaluates the feasibility of using the dispersionndata to characterize the coating's material properties. The measurementnof dispersion curves is based on a focusing PVDF transducer operating inna pulse/echo mode. An image displaying technique is used to determinenthe dispersion relation of Lamb waves from the measured data. Multiplendispersion curves of Lamb waves are accurately determined over a widenfrequency range (4 to 20 MHz). Lamb wave dispersion curves for thinnmetal sheets electrodeposited with nickel coatings are measured. Thenelastic constants of the nickel coating are determined by comparing thenexperimental dispersion data with the theoretical ones calculatednnumerically. Potential applications of this measurement method arenaddressed