Overview
Periodic preventive maintenance activities associated with aircraft subsystems is a significant part of the high costs associated with through life aircraft operations. Also, the understandably conservative approach to risk management, leads to premature component retirement, which is both highly inefficient and leading to a considerable carbon footprint. Minimising maintenance costs and carbon footprint are both major concerns within the whole of the aerospace industry.
If key components such as turbine engines had the ability to robustly, autonomously and continuously evaluate their structural health, and anticipate potential failures, maintenance costs could drastically decrease without compromising aircraft’s safety and reliability. This new maintenance paradigm of real-time in-situ health monitoring, would eliminate the need for the usual periodic preventive actions, allowing maintenance activities to evolve into a reactive paradigm, with extremely high savings as a result.
This project aimed at developing innovative technologies that will lead to reduce fuel consumption, noise and greenhouse gas emissions on power turboshaft engines. In order to provide useful data to optimize the development of each part of the turbo engine, Active Space Technologies SA (AST) proposes a solution for measuring in-situ strain and temperatures of the engine shaft.
Funding
Results
Executive Summary:
Periodic preventive maintenance activities associated with aircraft subsystems is a significant part of the high costs associated with through life aircraft operations. Also, the understandably conservative approach to risk management, leads to premature component retirement, which is both highly inefficient and leading to a considerable carbon footprint. Minimising maintenance costs and carbon footprint are both major concerns within the whole aerospace industry.
If key critical components, such as turbine engines, own the ability to robustly, autonomously and continuously evaluate their structural health, and anticipate potential failures, maintenance costs will drastically decrease without compromising aircraft safety and reliability. This new maintenance paradigm of real-time in-situ health monitoring, would eliminate the need for the usual periodic preventive actions, allowing maintenance activities to evolve into a reactive paradigm, with extremely high savings as a result.
Long term Active Space Technologies' developments aim at providing such capability for real-time continuous in-situ monitoring of critical parameters for evaluating the health of critical components, such as turbine shafts, gear teeth, and bearings. Although the current low TRL TSA activity was focused in lab applications, where monitoring physical parameters directly in rotating elements, and in harsh environments, were not possible with current available technology.
In the scope of TSA activity, Active Space Technologies developed a new telemetric concept, embracing several technical challenges requested by the Topic Manager, such as:
- Modularity: capability to adapt to different arrangements of strain and temperature channels;
- Reduced dimensions: allowing for integration inside the turboshaft engine;
- High speed measurement: acquire multiple strain gages with bandwidth in the order of 25 kHz;
- Resist to harsh environment:
> Rotating speed (up to 45,000 rpm);
> High temperature (up to 150 ºC);
> Oil mist.
The developed TSA concept is split in a highly innovative low power wireless slip ring and a miniaturized signal processing and conditioning unit, capable of multiplexing several simultaneous input channels, both systems fully developed in the scope of TSA. The designed wireless slip ring is composed by an inductive energy transfer link, capable of transmitting up to 10 W continuously and stable, avoiding the need for larger energy storage capacitors at the harsh environment, as well as transmitting low data rate communications for configuration and unit control; a complete high speed RF coupler (up to 10 Mbps) was designed to transmit the acquired sensory data from the rotating module, to the static gateway. The requested modularity was achieved by splitting the electronics design into three small boards: power conditioning; data acquisition, processing and communications; sensors signal conditioning. This approach allows a good modularity, because as long as the power and processing capacity is not exceeded, only the signal conditioning board needs to be redesigned for different applications.
The high accelerations imposed by the rotation of the shaft, which will be experienced by the rotating electronics, shown to be a major issue for the electronic components packages, which are not prepared to such high forces, induced by the acceleration. The solution adopted to overcome this problem was the reduction of the components mass, which drove the development to the use of bare die components, and wire bonding directly to the PCBs, a manufacturing technique known as chip-on-board.
The very final testing of TSA performance is still to be performed, but the test campaign carried out so far, has demonstrated the full potential of both wireless slip ring, and the complete control and acquisition loop of the TSA system. Further testing and performance analysis is to be performed in the near future, using the high speed test rig designed and manufactured by Active Space Technologies. This test rig is capable to spin up to 50,000 rpm, and has the possibility include a thermal chamber to heat up the testing unit, up to 200ºC.