NDTnet 1998 Aug, Vol.3 No.8

Full-Text - Abstract

Adaptive structures receive and process environmental information thus enabling them to react selfregulatively to changes of outer influences. Such a structural response allows compensation of troublesome mechanical deformation for shape control, artificially increased stiffness or effective damping of vibrations as examples of application. The resulting structural systems are termed smart, adaptive or intelligent structures. The adaptive function requires both inherent sensoric as actuatoric capabilities of the material - so new multifunctional materials have to be developed.

One possible variant of such adaptive material are fibre composites for example carbon fibre reinforced polymers (CFRP) with embedded piezoceramic plates as sensors and actuators. Development and optimization of this material system and manufacturing require nondestructive examination for structural characterization and detection of manufacture flaws. Furthermore, load-induced flaws which affect serviceability have to be proofed nondestructively. Among nondestructive methods ultrasonic techniques are of special interest for their possibilities of flaw detection and characterization.

The paper regards the problems of ultrasonic testing adaptive CFRP-structures with integrated piezoceramic plates. Different ultrasonic techniques with various image presentations are applied and evaluated. The examination results of specimens with different flaws, both manufacture as load-induced are presented and compared with cross-sections of the specimens. Examples of an assessment of the inner laminar structures of the material are given showing the influence of different manufacturing techniques (prepreg lamination, resintransfer-moulding).

Fig.: B-scan of a CFRP-laminate with broken piezoceramic actuator (schematic and original)

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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