Interaction of shear wave polarization and composite laminate layup: Experiment and modeling

The interaction of shear wave polarization and the fiber directions in a composite laminate makes shear waves a sensitive probe for evaluating ply orientation and sequence in a layup. The transmitted shear wave signal, with the transmitting and receiving transducers perpendicular to each other, can easily distinguish a [0/+45/90/−45]6 from a [0/+45/90/−45]3S, and detect an error in the form of a single misoriented ply: the 12th ply in [0/90/+45/−45]3S mistakenly placed at +45° instead of at −45°. Shear waves can therefore detect subtle but realistic layup anomalies in composite laminates. In this work, a model is developed for the propagation of shear waves through a laminate with arbitary ply orientation and sequence. Experimental results and model predictions are compared, and the model is used for identifying layup anomalies that are detectable with shear waves. Potential applications of this new method in nondestructive evaluation of composite laminates will be discussed. [Work supported by NSF I/U Ce...