Interaction of shear wave with fiber orientations in composite laminate: model and experiment

Abstract

Linearly polarized transverse (shear) waves propagating in the thickness direction of a composite laminate interact strongly with the fiber directions in the discrete plies of the laminate. Shear waves transmitted through or reflected from a laminate therefore contain information about its stacking sequence and layup orientation. In the case of transmission, one can also exploit the analogy with the polarizer-analyzer configuration in optics. It has been shown that the interaction between shear waves and fiber directions can lead to high sensitivity for the detection of certain errors in the layup or stacking sequence of a laminate. This paper describes a complete analytical model for the propagation of shear waves in a laminate using local and global transfer matrices. Transmitted and reflected signal amplitude as a function of angle and time (or frequency) can be predicted for a given input. Experimental results are also shown for a transmission setup that uses electromagnetic acoustic transducers (EMATs) for the generation and reception of normal incidence shear waves in cured and uncured composite laminates.