The paper presents guided elastic waves and their identification and damage interaction in a CFRP plate. After the excitation of a fiber transducer, different elastic waves emerge in a plate. By using specially developed 3D laser scanning software it was possible to specify the different wave modes. These wave modes have been described concerning their propagating velocities and different motion components. The interaction of different wave modes with introduced impact damage (7J) is shown. In some expts., it was proven that impact locations can be derived from the detected Lamb waves. This work is continued to develop structural health monitoring systems (SHM) for selected aircraft components (e. g. stringer elements, panels)

In order to reduce the CO2-emissions and to increase the energy efficiency, the operating temperatures of power plants will be increased up to 720°C. This demands for novel high-performance steels in the piping systems. Higher temperatures lead to a higher risk of damage and have a direct impact on the structure stability and the deposition structure. Adequately trusted results for the prediction of the residual service life of those high strength steels are not available so far. To overcome these problems the implementation of an online monitoring system in addition to periodic testing is needed. RWE operates the lignite power plant Neurath. All test and research activities have to be checked regarding their safety and have to be coordinated with the business operation of the plant. An extra bypass was established for this research and made the investigations independent from the power plant operating. In order to protect the actuators and sensors from the heat radiate d from the pipe, waveguides were welded to the bypass. The data was evaluated regarding their dependencies on the environmental influences like temperature and correction algorithms were developed. Furthermore, damages were introduced into the pipe with diameters of 8 mm to 10 mm and successfully detected by the acoustic method

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KurzfassungIn diesem Bericht wird die Entwicklung eines Structural-Health-Monitoring Systems, SHM, vorgestellt, das den Zustand der Rotorblätter von Windenergieanlagen überwachen und rechtzeitig vor Totalausfällen Strukturveränderungen detektieren und lokalisieren soll. Es basiert auf einer Kombination von Messtechniken aus den Bereichen der geführten Wellen im Ultraschallbereich und niederfrequenter Modalanalyse. Die Kombination beider Techniken ist bei bisherigen Rotorblattuntersuchungen bereits erfolgversprechend eingesetzt worden. Mittels Modalanlayse sind Aussagen zum Gesamtverhalten der Rotorblattstruktur möglich; gefährdete und stark beanspruchte Bereiche werden zusätzlich durch geführte Wellen im Ultraschallbereich überwacht.

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