Boston Univ., Dept. of Aerosp. and Mech. Eng., 110 Cummington St., Boston, MA 02215
Three-dimensional (3-D) textile composites provide a unique challenge to current ultrasonic NDE techniques. In 3-D textile composites, through-the-thickness stitching or tows provide reinforcement against delamination, which is common cause of failure in traditional aligned fiber laminates. However, standard nondestructive techniques for quality control and inspection are made less effective by the complex scattering created by the multidirectional fiber architecture. Although no single method will be suitable for detecting all potential defects and damage, the extent to which any given method is applicable is still relatively unexplored. The present research investigates the benefits of using plane waves to detect defects near the through-thickness reinforcements. Preliminary results will be presented on the effect of various structural parameters (e.g., interlaminar spacing, interlacing density, tow size, etc...) on the ultrasonic signal response.