Owing to the advantages associated with their very large strength-to-weight and stiffnessto-
weight ratios, composite materials are attractive for a wide range of applications. Increasingly,
high performance engineering structures are being built with critical structural components made
from composite materials. In particular, the importance of carbon-fiber reinforced plastics (CFRP)
has been generally recognized in both space and civil aircraft industries, and CFRP composite
laminates are widely used. It is very important to detect fiber orientation error in orthotropic
composite laminates because the layup of a CFRP composite laminates affects the properties of the
laminate, including stiffness, strength and thermal behavior. In this study, a new approach was
investigated on detection of fiber orientation with using two longitudinal and a shear wave
ultrasonic transducers for the orthotropic composite laminates. During testing, the most significant
problem is that the couplant conditions do not remain the same because of changing the viscosity of
the couplant. Therefore, making a design for generating shear wave with longitudinal transducers
would greatly aid in alleviating the couplant problem. A pyramid with an isosceles triangle was
made of aluminum in order to generate shear waves using two longitudinal transducers based on
ultrasonic-polarized mechanism. It is found that the shear wave was very sensitive to fiber of CFRP
composite. Finally, a CFRP composite material was nondestructively characterized in order to
measure fiber orientation error area using automated data acquisition C-scan system.
Parallel Computation of Ultrasonic Wave Propagation in Orthotropic Composite Materials
