Material characterization using leaky Lamb-waves

Quantitative material characterization of a two-layer isotropic composite plate having eight parameters (h
₁
, V
_L1
, V
_S1
, ρ
₁
, h
₂
, V
_L2
, V
_S2
, ρ
₂
) are presented; where h is the thickness, V
_L
and V
_S
are longitudinal and shear wave velocities respectively, and ρ is the density. Subscripts 1 and 2 refer to the plate and coating. An improved modal frequency spacing method (MFS) has been realized and three explicit MFS equations related to (h
₁
, V
_L1
, ρ
₁
, h
₂
, V
_L2
, ρ
₂
) are derived. In our numerical simulations we assume the values of h
₁
, ρ
₁
and h
₂
, and are able to evaluate V
_L1
V
_L2
and ρ
₂
using the above three MFS equations. The results show the high accuracy of our approach and also validate the sensitivity analysis of each parameter. Discussions on the evaluation of all eight material properties through inversion are also given