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Sensors integration and multifunctional layers

Technologies for integration of sensors and multifunctional layers in composite structures leading to low-weight sensing configurations

 

Enabling technologies

 

  • Miniaturization of sensors (including nanotechnology).
  • Manufacturing of thin polymer films with embedded microsensor arrays ready to be embedded in composites or glued on surface for SHM purposes.

 

Tools – methodologies

 

  • Sensor embedding techniques. Development of techniques for easier and faster embedding / surface attaching techniques of the manufactured thin films carrying the microsensors.
  • Sensor array design and optimization. Studies on best microsensor placement on different parts to be manufactured for SHM purposes. Results guide the manufacturing of a single or a few big size thin polymer films with the embedded microsensors. In that way the placement will be faster, more accurate, easier and with less wiring.

 

Current applications include multi modal sensor arrays on a flexible sensor substrate (see figure below). The sensor arrays are comprised of sensor nodes with local data processing and filtering capabilities. Sensors for pressure, temperature, thermal conductivity and strain have been investigated and integrated with the structural part.

 

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(a) multi-modal sensor node (b) Array of sensor nodes
 
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(a) The circuit model of n sensor nodes connected in series to form a continuous sensor (b) A hierarchical sensor array system

The hardware, which may include high-speed MEMS switches, can be embedded and the electric circuitry etched onto the smart composite laminate, which would then act as a ply of a laminated composite structure. It is expected future sensing technology would be comprised of wired connectivity at the local levels whereas wireless connectivity would be used at the global level. At the local level, the discrete or the continuous sensor components would be wire connected to a local bus with an antenna (receiver and transmitter) device, which would communicate wirelessly to the onboard flight computer. This would eliminate a significant number of wireless channels which otherwise would be needed to monitor large number of discrete sensors using wireless connectivity. It is envisioned that these techniques would be useful for both wireless and wired sensor arrays. The associated wired and wireless protocols have to be developed such that they do not interfere with the on-flight communications.
 
  • Molecular modelling for CNT microwire – microsensor growth: Theoretical studies on methodologies to guide the self-growing of CNT microwires on substrates and in a second stage to guide the self-assembly of microsensors.
  • Microwire – microsensor fabrications techniques: Tests and development of the techniques proposed by molecular modelling for the manufacturing of a thin polymer film with embedded microsensors and all the needed wiring.
 

Expected benefits

 

  • Miniaturized (smaller & lighter) sensors for SHM of composite or metallic parts
  • Ease of sensor placement as already embedded in larger thin films
  • Less wiring
  • Less effects on integrity when embedded in composites
  • Nanometer resolution
  • Low weight integrated sensor systems for health monitoring of structural parts

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