Propagation properties of Lamb waves in a functionlly graded material plate

For propagation of Lamb waves in a transversely isotropic functionally graded material (FGM) plate with material parameters varying continuously along thickness direction, power series technique is adopted for theoretical derivations and the phase velocity equations are obtained. Numerical calculations are performed to study the influence of material parameters graded variation on dispersion relations. These relations are compared with those in corresponding ceramic and metal plates, respectively. Further investigation is carried out to consider influence of material parameters graded variation on wave structures, behavior of Lamb waves in such typical inhomogeneous medium. Results obtained may provide theoretical basis for the ultrasonic characterization and testing of functionally graded materials and structures.