Abstract
Ultrasonic polar backscattering (PBS) was used to determine the local fiber orientation in a short glass fiber reinforced injection moulded polypropylene specimen. The backscattered intensity as a function of fiber angle was determined from a specially prepared specimen. The information from two scans, 90 deg apart, was needed from the injection moulded specimen. A computer algorithm was developed to compare the backscattered intensity of the unknown fiber orientation to the calibration specimen's fiber orientation. The angle at which the difference between the functions was minimized was taken as the fiber orientation for that local region. The results were compared with the fiber orientations determined by classical methods. At regions close to the surface, a good correspondence between both methods has been obtained.