HOCHAUFLÖSENDE VERFAHREN ZUR ZERSTÖRUNGSFREIEN PRÜFUNG

Abstract

 The paper presents some concepts for non-destructive inspection of aeronautic, automotive and energetic components. Eddy current techniques are investigated to detect surface cracks, tungsten carbide inclusions and overheating of aircraft engines components from titanium and nickel alloys. High frequency sensors are able to visualize local variations of conductivity and magnetic permeability ready for interpretation. In aviation carbon fibre-reinforced plastics increasingly become popular for fuselage applications. Eddy currents can estimate the fibre orientation and gaps between the tapes resulting  from manufacturing. In automotive industry eddy 
current sensor arrays provide visual information about hidden cavities and oxide inclusions in aluminium castings. For the inspection of heat exchanger tubing in the chemical industry imaging eddy current probes are under progress also providing information from the back side of the tube wall. 
Future aircrafts should be able for structural health monitoring. One of the favourite techniques is sending Lamb wave along the thin walled fuselage interacting with possible defects. These waves can be generated by integrated or applied piezo-electric transducers directly on the component under inspection. The paper demonstrates some encouraging results obtained by scanning laser vibrometry.