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Laser induced acoustic emission for process control and materials testing

Controle en Fabrication et Tests de Materiaux grace a l'Emmission Acoustique induite par Irradiation Laser
: Meyendorf, N.; Morgner, W.; Benzinger, T.

Comite Europeen sur les Essais Non Destructifs -ECNDT-, Paris:
6th European Conference on Non-Destructive Testing '94. Vol.1
Paris, 1994
European Conference on Non-Destructive Testing <6, 1994, Nizza>
Fraunhofer IZFP ()
acoustic emission; laser; material testing; process control; Prozeßüberwachung; Schallemission; Schweißen; welding; Werkstoffprüfung

Radiating a specimen surface with focused laser beams, involving the well-known photoacoustic effects, is accompanied by acoustic emissions which are attributable to various sources. In case of laser radiation with lower power density, thermoelastic effects in the specimen can produce defects which may grow and, in turn, result in acoustic emission. Initial tests showed that critical areas can be detected in sensitive terms preferably in composite materials even before macroscopically detectable failure occurs. Pulsed radiation with sufficiently high power density causes plasma eruptions to occur. The resultant pressure waves can be detected by means of the acoustic emission technique, thus opening up new approaches to monitoring laser machining processes.