Paper number 132

CONTINUOUS DAMAGE MONITORING TECHNIQUES FOR LAMINATED COMPOSITE MATERIALS

M. Surgeon, M. Wevers

Department of Metallurgy and Materials Engineering (KULeuven), De Croylaan 2, B-3001 Heverlee, Belgium

Summary

The increasing use of composite materials in loaded structures and the typical distributed nature of damage in these materials has created a need for reliable and efficient damage monitoring techniques. Preferably, these techniques should have continuous detection capabilities as this makes it possible to eliminate the high cost of a periodic inspection scheme. This paper will discuss two different approaches to continuous damage detection : optical fibre technology and modal acoustic emission (MAE). By embedding optical fibres in composite materials and by continuously monitoring the changes in properties of light transmitted through these fibres, damage initiation and growth can be detected. This has been demonstrated by performing tensile tests on quasi-isotropic laminates and correlating the optical fibre observations with results obtained by the classic acoustic emission and replica techniques. Modal acoustic emission is a new approach to acoustic emission testing which uses plate wave theory as a theoretical background. Laboratory testing has shown that this new analysis procedure offers distinct advantages over the classic AE analysis techniques.

Keywords

damage monitoring, continuous, optical fibre, acoustic emission, plate wave theory