Accession Number : ADD011210

Title :   Ultrasonic Inspection of Composite Materials.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Bar-Cohen,Y ; Crane,R L

Report Date : 03 Jul 1984

Pagination or Media Count : 10

Abstract : A method of ultrasonically inspecting the internal structure of a multi-ply composite material using ultrasonic transducers includes the steps of positioning an ultrasonic transmitter in acoustical contact with one surface of the material, directing a beam of acoustic energy into the material with the angle of incidence of the beam with respect to the surface being less than the second critical angle for the material but greater than normal to the surface, and receiving the reflected energy. In one embodiment, the transmitting and receiving transducers are positioned with their axis perpendicular to the orientation of the reinforcing fibers within the ply being inspected. Internal cracks within each layer of the composite material can be detected along with information regarding their length and number. Further, by precessing the transducers, the orientation of the fibers within each ply will be revealed and this information may be used to confirm proper construction of the composite.

Descriptors :   *Patents, *Composite materials, *Ultrasonic tests, *Inspection, Cracks, Internal, Fibers, Orientation(Direction), Reinforcing materials, Transducers

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE