Space composite structures life-cycle monitoring

To integrate sensors in composite structural components in order to monitor and control the manufacturing, assembly, integration, testing and the component performance during operation.

Composite materials are widely used in space applications as they offer very high specific stiffness and strength properties. Their nature and manufacturing processes offer the possibility of embedding sensors for measuring fundamental quantities that can be used to monitor the structure during its entire life-cycle. Fiber optical sensors, for instance, are a promising candidate for this application. Optical fibers are compatible with common resins; they can be embedded into composites during conventional manufacturing processes such as hand layup, filament winding, tape placement, etc. These sensors allow discrete (e.g. fiber Bragg gratings, embedded reflectors coupled with Fabry-Perot interferometry) or high-resolved distributed (e.g. variable frequency Mach-Zehnder interferometry) measurement of strain, temperature, pressure in a static or dynamic environment with very high accuracy and sensitivity. There are other possible sensor technologies such as piezoelectric transducers, and this activity will develop a trade-off for space applications.Measured quantities can be used to monitor the manufacturing process, for instance pressure and temperature distribution and residual strain measurements. The same sensing system can be used to monitor excessive loads introduced in the component during assembly; to collect data for models validation during testing activities; and to monitor the performance of the structure during operation up to disposal.The activity aims at demonstrating the concept of life-cycle monitoring via embedded sensors in a composite structure with the following main tasks:- Identify space structural component(s) to be studied (e.g. panel, strut, cylindrical/conical barrel etc.) and its operational environment (applications for re-usability are preferred).- Identify key parameters to be monitored that will be used to assess the composite component performance during its life-cycle.- Identify measuring system(s) able to measure and record the key parameters and that can be integrated within the component of point during its manufacturing stages.- Design a composite component with the integrated monitoring system as well as means of data acquisition with minimal interference to AIT. The integration of the sensing system shall not affect the main performance of the component.- Validation of the system designed: (i) manufacturing process monitoring; (ii) monitoring during representative testing.