Hybrid inversion of elastic moduli of composite plates from ultrasonic transmission spectra using PVDF plane wave sensor

Determination of the elastic moduli of polymer matrix based structural composite materials is necessary to characterize their strength after fabrication and while in service. This paper reports a modification to goniometry based ultrasonic through transmission data collection by using wide aperture low cost polyvinylidene fluoride (PVDF) based receiver. The use of PVDF based receiver more than satisfies the plane-wave conditions required from measurement. The use of a hybrid inversion technique which combines genetic algorithm based evolutionary approach, critical angle information and the use of stiffness invariants is implemented for determination of stiffness values from experimental transmission spectra measurements. Results for unidirectional and a multi-layered composite laminate are presented.