Location

La Jolla, CA

Start Date

1981 12:00 AM

Description

This paper describes ongoing research efforts to evaluate thermographic techniques for locating flaws or damage in structural fiber composite laminates. An infra-red camera with video isotherm readout is used to identify perturbations in uniform or linear thermal fields which may be caused by presence of flaws or damage such as matrix cracks, delaminations, blind side impact damage, and partial through holes. This procedure has potential for rapid qualitative screening of large surface areas. Potential defective areas may then be analyzed by a more accurate (but more time consuming) method . Two techniques are discussed; externally applied thermal field (EATF) and stress-generated thermal field (SGTF). The EATF technique involves applying heat to a composite structure and observing theresulting transient thermal pattern. The SGTF technique requires stress cycling to create hot spots in regions of high stress concentrations adjacent to flaws or damage sites.

Book Title

Proceedings of the ARPA/AFML Review of Progress in Quantitative NDE

Chapter

5. Composites, Adhesive Bonds, New Phenomena and Problems

Pages

60-68

Language

en

File Format

application/pdf

Share

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Jan 1st, 12:00 AM

NDT of Composites by Thermography

La Jolla, CA

This paper describes ongoing research efforts to evaluate thermographic techniques for locating flaws or damage in structural fiber composite laminates. An infra-red camera with video isotherm readout is used to identify perturbations in uniform or linear thermal fields which may be caused by presence of flaws or damage such as matrix cracks, delaminations, blind side impact damage, and partial through holes. This procedure has potential for rapid qualitative screening of large surface areas. Potential defective areas may then be analyzed by a more accurate (but more time consuming) method . Two techniques are discussed; externally applied thermal field (EATF) and stress-generated thermal field (SGTF). The EATF technique involves applying heat to a composite structure and observing theresulting transient thermal pattern. The SGTF technique requires stress cycling to create hot spots in regions of high stress concentrations adjacent to flaws or damage sites.