In the EU-funded Clean Sky project SWISSMODICS, coordinated by CSEM, experts have designed an image sensor for integration into aircraft composite structures. This innovation aims to identify damage and defects, streamlining inspections and minimizing the need for prolonged downtimes or disassembly of aircraft.
Aircraft undergo regular inspections, both as part of routine maintenance and after experiencing impacts, such as those from ground support equipment at airport gates or in-flight bird strikes. The impact damage on an aircraft's structure may not always be visible at the point of contact.
That’s especially true for aircraft made from composite materials, which are increasingly common as composites weigh less than conventional materials. When a composite material is impacted, that creates a shock wave that propagates through the material and may cause damage – called delamination – at a location distant from the impact site making the damage harder to detect.”
A variety of methods are available for detecting delamination in composites. However, they involve inspections that require aircraft to be grounded for long periods of time or even disassembled – both of which are costly processes.
In SWISSMODICS, three partner organizations – CSEM, Jean Monnet University in Saint-Etienne, France, and Almay Technologies in Chauvigny, France, – have developed a broad-wavelength spectrum image sensor , while ensuring a slim profile enabling a seamless integration directly into the aircraft’s composite structure to detect damage. This new technology could substantially shorten inspection times and reduce the inconvenience caused to both airlines and passengers, especially when planes must be grounded at the last minute for unplanned maintenance inspections.
The new device was designed to detect a broad spectrum of wavelengths: visible, X-ray and infrared. Operators can select the most suitable range from three options to effectively detect damage or inspect specific areas
The sensor includes an electronic chip containing an array of 512 x 512 pixels on which different types of sensitive layers (quantum dots / perovskite) have been deposited, to be sensitive to X-ray, visible and short-wave infrared up to 1300 nm. This is to our knowledge the worldwide first CMOS X-ray sensor with direct conversion in quantum dots. It not only detects X-ray photons, but also visible light and infrared light up to a wavelength of 1300 nm. The sensor was used successfully to detect defects in composite samples. The project, completed in November 2023, showcased a wide-spectrum sensor with outstanding X-ray detection capabilities. The very high absorption coefficient of the detecting layer enables thin X-ray detectors, which is key for their incorporation in composite structures. The use of standard processes to deposit these layers will enable the development of low cost sensors, that support not only the development of lighter aircraft, with all the environmental benefits that will bring, but will also benefit other markets outside the aeronautical one.
