Active Tagging Non-Destructive Evaluation Techniques for Full-Scale Structural Composite Elements
VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG CENTER FOR INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
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A health monitoring technique is presented for on-site particle tagging non-destructive evaluation NDE of a full-scale structural element of advanced composites. Conventional non-destructive evaluation methods are not very effective in monitoring the material conditions of advanced composite and adhesive joints. A technology that has been proposed to enhance the inspectability of advanced composites is the particle tagging technique Rogers, et al., 1995, Zhou, et al., 1995. This technique which has been previously demonstrated on small scale, laboratory samples Rogers, et al., 1996a, Rogers, et al., 1996b, Giurgiutiu, et al., 1996 is now developed to scaled up on full-scale structural elements. The concepts for large scale tagged composite inspection build on the previously developed small scale concepts. The technique relies on comparing changes in local-area mechanical properties of the structure to identify damage. Unlike conventional passive tagging NDE inspection, the technique uses an electromagnet exciter to interrogate tagged composites. A laser Doppler vibrometer is used for high-speed and non-contact surface vibration detection. An accept-reject criteria based on the signature pattern difference of a healthy and a damaged structure is then applied to extract an index of the health of the structural elements. The experimental results of the active particle tagging inspection shows a variation in the dynamic response of the specimens when defects andor damage are presents. The variation could be used to diagnose and to monitor the integrity of materials.
- Structural Engineering and Building Technology
- Test Facilities, Equipment and Methods