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Fribourg, Switzerland

Nicchiotti G.,Meggitt Sensing Systems
IEEE Aerospace Conference Proceedings | Year: 2014

Pushed by digital systems development and the pressure to reduce costs, in the last 40 years health monitoring (Hm) capabilities evolved from simple Built In Tests to system health prognostics, causing the development of new maintenance and operation concepts and new business models. Hm functions allow business growth by maximizing availability, optimizing the logistics, improving productivity and reducing maintenance costs and nowadays they have assumed a central role in aviation business. This role has to be captured by Hm system providers in order to fully exploit the opportunities provided by the market. To define Hm requirements is a very complex task as it necessitates considering many complex interrelated aspects such as costs reduction, concept of operations and business models. Nevertheless very little guidance exists about Hm requirements capture and this gap represents one of the main blockers to the diffusion of Hm systems. This work will then try defining a structured way to produce good Hm high level requirements. House of Quality (HoQ) has been identified as a structured but flexible methodology, which allows taking into account all the complexity of Hm and integrating business, maintenance and operational aspects. The research guideline for the design of the Hm HoQ matrices is based on the understanding of the economic value created by Hm and on the results of the total life asset cost analysis. The use of the proposed method has been demonstrated and validated through case studies where the high level Hm requirements for a metering valve and a landing gear monitoring system have been investigated. The results obtained in this phase proved that the methodology is credible as it confirmed some of the conclusions previously obtained by using traditional approaches; in addition to this new aspects are brought into consideration, making the requirements definition process more complete. © 2014 IEEE.

Wisniewiski D.,Meggitt Sensing Systems
21st International Congress on Sound and Vibration 2014, ICSV 2014 | Year: 2014

As the commercial aerospace sector continues to grow at an astonishing rate, advances in sensing technology are keeping pace. One such advance being incorporated into airframe systems is a Tire Pressure Monitoring System (TPMS) which provides continuous, real-time pressure monitoring in the harsh environment seen in aircraft landing gears. This capability translates to money saved in low lifecycle cost; minimal maintenance downtime; fuel savings during taxiing, take-off and landing; and increased life of the tire. Additionally, passenger comfort and safety is ensured with proper tire inflation levels. Accordingly, improved performance and increased reliability demands are being imposed on the pressure transducer, which is the centerpiece of TPMS. But the pressure transducer's contribution to reliable, real-time pressure monitoring over multiple years of operation is predicated upon the inherent long-term stability it must possess. The mechanism (or "heart") of the pressure transducer is the silicon Micro Electro-Mechanical System (MEMS) element itself. Furthermore, it is at this fundamental level where the long-term stability is established and needs to be quantifiably measured. In order to establish direct physical insight into the mechanism of long-term stability, an innovative High Pressure, High Temperature (HPHT) chamber has been designed and manufactured to permit testing of the silicon MEMS element itself through a process of mechanically "floating" the silicon MEMS element while simultaneously subjecting it to the extreme environment of pressure (3447 kPa) and temperature (260°C) seen in aircraft landing gear. The HPHT chamber is scalable to permit multiple specimens to be tested at one time - both at the silicon MEMS element level as well as higher assembly levels - so that reasonable conclusions can be drawn about long-term stability from a statistically significant data population. The HPHT chamber, an ideal platform offering multiple levels of configurability for performing long-term stability measurements of pressure transducers, is presented.

Holst T.,Meggitt Sensing Systems
Proceedings for the Joint Conference: MFPT 2013 and ISA's 59th International Instrumentation Symposium, ISA 2013: Sensors and Systems for Reliability, Safety and Affordability | Year: 2013

•E-32 committee developing AIR to provide Aerospace community information about the use of time of arrival and tip clearance measurements for engine health management applications. •Scope and Rationale approved, goal to have review document within the next year. •Not a lot of time of arrival or tip clearance experts on SAE committees, SAE needs your input during AIR development & review!.

Wisniewiski D.,Meggitt Sensing Systems
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Advancements in the aerospace, defense and energy markets are being made possible by increasingly more sophisticated systems and sub-systems which rely upon critical information to be conveyed from the physical environment being monitored through ever more specialized, extreme environment sensing components. One sensing parameter of particular interest is dynamic pressure measurement. Crossing the boundary of all three markets (i.e. aerospace, defense and energy) is dynamic pressure sensing which is used in research and development of gas turbine technology, and subsequently embedded into a control loop used for long-term monitoring. Applications include quantifying the effects of aircraft boundary layer ingestion into the engine inlet to provide a reliable and robust design. Another application includes optimization of combustor dynamics by "listening" to the acoustic signature so that fuel-to-air mixture can be adjusted in real-time to provide cost operating efficiencies and reduced NOx emissions. With the vast majority of pressure sensors supplied today being calibrated either statically or "quasi" statically, the dynamic response characterization of the frequency dependent sensitivity (i.e. transfer function) of the pressure sensor is noticeably absent. The shock tube has been shown to be an efficient vehicle to provide frequency response of pressure sensors from extremely high frequencies down to 500 Hz. Recent development activity has lowered this starting frequency; thereby augmenting the calibration bandwidth with increased frequency resolution so that as the pressure sensor is used in an actual test application, more understanding of the physical measurement can be ascertained by the end-user. © 2015 SPIE.

Jurkow D.,Wroclaw University of Technology | Dabrowski A.,Wroclaw University of Technology | Golonka L.,Wroclaw University of Technology | Zawada T.,Meggitt Sensing Systems
International Journal of Applied Ceramic Technology | Year: 2013

Design procedure, technology and basic properties of a piezoelectric Low Temperature Co-fired Ceramics (LTCC) accelerometer are presented in this paper. The sensor consists of a LTCC membrane with a seismic mass. Meggitt InSensor PZT thick film has been applied as the sensing material. Finite element method (FEM) has been used to analyze the impact of the sensor geometry (membrane thickness, membrane and seismic mass radii) and PZT thick film placement on basic properties (sensitivity and bandwidth) of the device. The LTCC process was optimized in order to create thin and planar ceramic membrane with relatively huge seismic mass. Selected properties of the sensor have been measured and compared with the simulated ones. © 2013 The American Ceramic Society.

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