Development of an Optical/Acoustic Method for the Remote Non-Destructive Inspection of Large Area Composite Materials

Period of Performance: 09/05/1995 - 09/30/1996


Phase 2 SBIR

Recipient Firm

Holographics, Inc.
4401 11th Street
Long Island City, NY 11101
Principal Investigator


A feasibility study has been conducted into a non-destructive method of detecting faults in composite materials, particularly those used in the manufacture of components used in the aircraft industry. The system includes using a noncontacting acoustic exciter unit with a unidirectional output properties delivering a focused 150 dB pulse with a bandwidth of about 30 kHz. The surface of the object under analysis was interrogated with a laser velocimeter. Results illustrated in the Phase I study and the Phase II proposal indicated the technique can successfully be applied to the detection of faults in both honeycomb laminated materials as well as solid carbon fiber laminates where both in-plane and out of plane cracking was clearly shown. The proposal suggests the development of a system that is robust, user friendly and NDT technician usable in factory, ramp and hangar situations and automatically accounts for curved and object surfaces which are not perpendicular to the common system axis. As discussed in the report, modern passenger aircraft are greatly increasing their use of composite materials. Other than visual inspection, tapping, or manually scanning with an acoustic crystal, the problem of NDI of composites in the field, ramp, or hangar has not been addressed. Yet the problems are potentially vast when such components as, say, a vertical stabilizer is considered. A Phase III or any resulting commercial product will address these problems in a remote or non-contacting manner.