Equivalent elastic modulus measurement of cross-ply composite plates using Lamb waves

This paper proposes a simple and effective Lamb wave-based measurement method for the elastic moduli of cross-ply composite plates, considered equivalent to a single-layer orthotropic plate with nine independent elastic constants. The effects of theses constants on the phase velocities of the fundamental S0 and A0 modes are investigated. The phase velocity of the S0 mode depends only on the equivalent tensile elastic modulus and in -plane Poisson's ratio in the low-dispersive frequency-thickness product regime, whereas the phase velocity of the A0 mode depends almost only on the equivalent shear elastic modulus. Moreover, the in-plane Poisson's ratio of cross-ply laminates changes sufficiently small to neglect its effect on the phase velocities of the S0 mode. Therefore, the tensile and shear elastic moduli of the plates can be estimated using the S0 and A0 modes, and the mapping relations between the phase velocities of these modes and the elastic moduli are established. The proposed approach has been numerically and experimentally tested on cross-ply carbon fiber reinforced lami-nates, and validated by theoretical values and conventional tensile tests.