Development, implementation and testing of an online monitoring system for production processes and structural behavior of components in aerospace sector
For the reduction of weight the concept of „Damage Tolerant Design“ has been successfully implemented in the aerospace industry since several decades. This concept is based on the idea, that a certain amount of defects can be tolerated in a structural component, before it has to be repaired or exchanged. To guaranty the structural integrity of such a component continuous non-destructive inspections have do been done, leading to down times of aircrafts. In addition the amount of structural components made of CFRP has been increased strongly in the last decade, but their potential has not been exhausted due to uncertainties in the production process and the prediction of the residual life (higher safety factors compared to metal structures).
If such a non-destructive inspection system could be permanently applied to structures of interest especially to composite structures and operated online (Structural Health Monitoring), especially in distributed and difficult to access areas, a strong reduction in the down time and subsequent costs of maintenance and also a reduction in weight could be expected.
Besides the monitoring of the usage, process monitoring of automated production process such as resin infusion of polymer composite structures became important. Therefore concepts for integrated process- and structural health monitoring for high quality structures are required.
AAC is developing methods and sensors for production process monitoring as well as concepts and algorithms for the off- and online damage detection, quantification and residual life time prediction for composite structures based on passive and active ultrasonic methods like Acoustic Emission, Guided Ultrasonic Waves and Phased Array Ultrasonic waves together with local strain approaches measured by distributed fibre optic sensors.
The following data acquisition systems are available at AAC
- 6 AE channel acoustic emission system AMSY 5 from Vallen (2 parametric channels)
- Combined hybrid active (guided ultrasonic wave) / passive (acoustic emission) SHM system from Physical Acoustics (8 AE channels / 4 multiplexed signal generation channels / 8 parametric channels)
- LCR meter for impedance spectroscopy (cure monitoring)