Definition of Test Conditions for High Voltage Aerospace Systems Using the IAGOS Atmospheric Dataset 2018-01-1931
Aerospace electrical systems are continuing to increase their voltage levels to meet the on-board
power demands of more-electric aircrafts (MEAs) where hydraulic and pneumatic systems are
replaced with electrical equivalents. Higher power demands are leading to the use of higher
voltages and as such it is essential to explore the behaviour of the insulation system in the
aerospace environment. This degradation takes place in situations where equipment can be exposed to an aerospace environment consisting of operating temperatures up to 250 °C or as low as - 50 °C, varying air pressure, humidity and ozone. Understanding the impact of these variables on the ageing of high voltage insulation systems is crucial in predicting lifetime over the service life of an aircraft.
This paper describes the results derived from an analysis of data within the In-service Aircraft
for a Global Observing System (IAGOS) database. This database includes 47,000 flight profiles.
They are analysed by examining flight temperatures, relative humidity, water and ozone concentration that can accelerate the chemical, electrical, mechanical ageing and degradation mechanisms of polymeric insulation. This data is then fed into a COMSOL model to predict worst case conditions using chemical kinetics to predict lifetime of insulation. Comparing environmental conditions obtained from the IAGOS database with the test conditions standard, RTCA DO-160, it has been shown that there is some variance in maximum and minimum temperature peaks which are not accounted for and included in current standards. The data that has been analysed should be considered for adoption by aerospace standards to ensure that equipment is tested and aged in conditions appropriate to its application. The treated IAGOS data allows the comparison of relative life of insulation systems in an aerospace application against similar ground based systems. Current standards may not provide representative testing conditions for aerospace equipment and therefore give inaccurate predictions of material lifetime and component service life.
Hasti Haghighi, Ian Cotton, Richard Gardner, Bastien Sauvage
University of Manchester, Université de Toulouse
Aerospace Systems and Technology Conference