WAVE-PROPAGATION IN COMPOSITE-MATERIALS WITH FIBER WAVINESS

A discrete ray tracing model based on elastodynamic ray theory was dev eloped and applied to a composite material with fibre waviness. The va rying anisotropy of this composite causes the ultrasonic waves to trav el along curved paths. Particular attention was paid to the comparison with experimental measurements in order to check the applicability of the method for non-destructive characterization of fibre waviness, es pecially in the high frequency regime. A specimen with intentional fib re waviness was fabricated by winding prepreg tape around a specially designed mandrel. The specimen was tested in the through-transmission mode using special ultrasonic techniques for thick composites. The the oretical model and experimental results agree, at least with regard to the period of fibre waviness.