Structural Health Monitoring:
Within the framework of several German and European projects, Fraunhofer LBF is developing concepts for structural health monitoring (SHM), designed to monitor critical components. As part of the European "Clean Sky" project, research scientists are designing, producing and testing smart systems to measure the loads acting on a component and monitor its structural integrity. Loads are determined by means of optical fibers through strain measurement.
For applications in aeronautics this technology is used and validated in conjunction with fiber reinforced composite components. Coupons and structural components with integrated optical fibers are manufactured in our laboratories and tested under close-to-real loading conditions. Monitoring of structural integrity is achieved by using active and passive methods, based on piezo ceramic sensors. These devices monitor the integrity of a component by means of acoustic methods, using the propagation of high-frequency waves as a measurement signal for detecting structural integrity and identifying damage. Fiber reinforced composite components present particular challenges in terms of structural integrity, due to their specific damage mechanisms and structural properties. Manufacture of the fiber reinforced composite structures takes place in Fraunhofer LBF's laboratories. The concepts and models developed by the Institute are analyzed and validated by using high-performance measuring systems.
The range of Fraunhofer LBF's competences also includes the application of nanomaterials used to enhance safety in the aeronautical sector. CNT Carbon Nano Tube based "Bucky Paper" is used on aircraft wings to avoid icing at critical positions. This is another area in which the Institute develops, implements and tests concepts for integrating these materials. In partnership with its European partners Fraunhofer LBF is engaged in the development of new SMH systems and safety concepts for the "green" aircraft of the future.
Fiber reinforced composite components offer a huge potential, which, as yet, has not been fully realized in practical application. Monitoring systems developed by Fraunhofer LBF enable the mechanical properties and damage occurring on the component to be observed. The Institute offers SMH concepts including production of the component, integration of sensors and the required measuring equipment for experimental verification.