Fraunhofer Institute for Applied Polymer Research
Fraunhofer Institute for Applied Polymer Research

Strategies for extending the service life of complex composite components through integrated sensor technology for structural monitoring

Condition monitoring of lightweight components is crucial for the safety, service life, efficiency and cost optimisation of structures. However, the use of sensors harbours the risk that the components may be weakened by the intervention. The LeCoBaSe project aims to develop concepts for improving sensor integration.

Technical demand:

  • Longer service life of the fibre composite components
  • Fewer safety parameters, resulting in lighter components
  • Sensor technology on the component is unprotected, holds poorly and does not detect the interior
  • Sensors between the composite layers act as predetermined breaking points (delamination)

Scientific-technical solution:

  • New concepts for sensor insertion (new sensor geometries such as structured grids)
  • High molecular weight, phase-separating block copolymers in cylindrical geometry as resistive sensors
  • Reduction of the risk of delamination through improved bonding
  • Reduction of the risk of delamination by means of lattice structure (avoidance of predetermined breaking points)
  • Reduction of the risk of delamination due to alternative materials with improved adhesion
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  • The functional integration of sensors directly into (load-bearing) lightweight structures is an important development focus for monitoring the condition and service life of highly stressed lightweight components. Continuous monitoring can reduce the safety parameters for components based on composite fibre materials and thus reduce the component weight, while the service life can also be significantly increased. Particularly in CO2-intensive areas such as aviation, a significant reduction in CO2 emissions can be achieved, both through lower fuel consumption and through the increased service life of the components. The use of sensors in (load-bearing) fibre composite plastic components is currently difficult, as inserting them directly into the structure can weaken the component; in particular, large sensors based on fluoropolymers such as PVDF can act as unwanted predetermined breaking points between the composite layers and lead to delamination and thus to component failure.

    The project aims to develop concepts for improving sensor integration. Two overlapping strategies are to be utilised here: New sensor geometries for piezoelectric sensors, such as lattice structures, are to be developed. As these structures do not form a continuous surface, the connection between the individual composite layers is maintained and the risk of delamination is reduced. As a second strategy, high-molecular, phase-separating block copolymers based on polystyrene/polyvinylpyridine developed by the PAZ are being evaluated as resistive sensors for pressure detection, whereby the new sensor geometries are to be used here. 

  • Funding

    This project is funded as part of the Fraunhofer-Gesellschaft's internal programmes.