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Aircraft Gas Turbine

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H K D H Bhadeshia – One of the best experts on this subject based on the ideXlab platform.

  • bearing steel microstructures after Aircraft Gas Turbine engine service
    Materials Science and Technology, 2014
    Co-Authors: J R Nygaard, M Rawson, P Danson, H K D H Bhadeshia
    Abstract:

    AbstractThe microstructure of Aircraft Gas Turbine engine bearing steel has been characterised after service in Rolls-Royce Trent™ engines, with the focus on surface condition and the consequences of sliding contact. Carbide populations at the surfaces of rolling elements are found depleted by 30% after 30 000 h engine service. A single ball failure occurred after this period, leading to fatigue spalling that initiated below the contact surface. Comparisons between unused bearing raceways and those that have experienced service revealed that the microstructures resulting from secondary hardening remain remarkably stable. Plastic flow along the direction of rolling is confined to a shallow zone <2 μm beneath the contact surfaces. Transmission elecelectron microscopy has revealed a new deformation mechanism in these bearing steels, in the form of mechanical twinning at interfaces and prior austaustenitein boundaries. It is demonstrated that workhardening occurs to a depth of 1 mm in the raceway that has experie…

  • Bearing steel microstructures after Aircraft Gas Turbine engine service
    Materials Science and Technology, 2014
    Co-Authors: J R Nygaard, M Rawson, P Danson, H K D H Bhadeshia
    Abstract:

    AbstractThe microstructure of Aircraft Gas Turbine engine bearing steel has been characterised after service in Rolls-Royce Trent™ engines, with the focus on surface condition and the consequences of sliding contact. Carbide populations at the surfaces of rolling elements are found depleted by 30% after 30 000 h engine service. A single ball failure occurred after this period, leading to fatigue spalling that initiated below the contact surface. Comparisons between unused bearing raceways and those that have experienced service revealed that the microstructures resulting from secondary hardening remain remarkably stable. Plastic flow along the direction of rolling is confined to a shallow zone

J R Nygaard – One of the best experts on this subject based on the ideXlab platform.

  • bearing steel microstructures after Aircraft Gas Turbine engine service
    Materials Science and Technology, 2014
    Co-Authors: J R Nygaard, M Rawson, P Danson, H K D H Bhadeshia
    Abstract:

    AbstractThe microstructure of Aircraft Gas Turbine engine bearing steel has been characterised after service in Rolls-Royce Trent™ engines, with the focus on surface condition and the consequences of sliding contact. Carbide populations at the surfaces of rolling elements are found depleted by 30% after 30 000 h engine service. A single ball failure occurred after this period, leading to fatigue spalling that initiated below the contact surface. Comparisons between unused bearing raceways and those that have experienced service revealed that the microstructures resulting from secondary hardening remain remarkably stable. Plastic flow along the direction of rolling is confined to a shallow zone <2 μm beneath the contact surfaces. Transmission electron microscopy has revealed a new deformation mechanism in these bearing steels, in the form of mechanical twinning at interfaces and prior austenite grain boundaries. It is demonstrated that workhardening occurs to a depth of 1 mm in the raceway that has experie...

  • Bearing steel microstructures after Aircraft Gas Turbine engine service
    Materials Science and Technology, 2014
    Co-Authors: J R Nygaard, M Rawson, P Danson, H K D H Bhadeshia
    Abstract:

    AbstractThe microstructure of Aircraft Gas Turbine engine bearing steel has been characterised after service in Rolls-Royce Trent™ engines, with the focus on surface condition and the consequences of sliding contact. Carbide populations at the surfaces of rolling elements are found depleted by 30% after 30 000 h engine service. A single ball failure occurred after this period, leading to fatigue spalling that initiated below the contact surface. Comparisons between unused bearing raceways and those that have experienced service revealed that the microstructures resulting from secondary hardening remain remarkably stable. Plastic flow along the direction of rolling is confined to a shallow zone

Asok Ray – One of the best experts on this subject based on the ideXlab platform.

  • Multi-sensor information fusion for fault detection in Aircraft Gas Turbine engines:
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2012
    Co-Authors: Soumik Sarkar, Asok Ray, Soumalya Sarkar, Kushal Mukherjee, Abhishek Srivastav
    Abstract:

    The article addresses data-driven fault detection in commercial Aircraft Gas Turbine engines in the framework of multi-sensor information fusion and symbolic dynamic filtering. The hierarchical decision and control structure, adopted in this article, involves construction of composite patterns, namely, atomic patterns extracted from single sensors, and relational patterns representing cross-dependence between a pair of sensors. While the underlying theories are presented along with necessary assumptions, the proposed method is validated on the NASA C-MAPSS simulation test bed of Aircraft Gas Turbine engines; both single-fault and multiple-fault scenarios have been investigated. Since Aircraft engines undergo natural degradation during the course of their normal operation, the issue of distinguishing between a fault and natural degradation is also addressed.

  • Symbolic identification for fault detection in Aircraft Gas Turbine engines
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2011
    Co-Authors: Subhadeep Chakraborty, Soumik Sarkar, Asok Ray
    Abstract:

    This article presents a robust and computationally inexpensive technique of component-level fault detection in Aircraft GasTurbine engines. The underlying algorithm is based on a recently developed statistical pattern recognition tool, symbolic dynamic filtering (SDF), that is built upon symbolization of sensor time series data. Fault detection involves abstraction of a language-theoretic description from a general dynamical system structure, using state space embedding of output data streams and discretization of the resultant pseudo-state and input spaces. System identification is achieved through grammatical inference based on the generated symbol sequences. The deviation of the plant output from the nominal estimated language yields a metric for fault detection. The algorithm is validated for both single- and multiple-component faults on a simulation test-bed that is built upon the NASA C-MAPSS model of a generic commercial Aircraft engine.

  • Semantic sensor fusion for fault diagnosis in Aircraft Gas Turbine engines
    Proceedings of the 2011 American Control Conference, 2011
    Co-Authors: Soumik Sarkar, Dheeraj Sharan Singh, Abhishek Srivastav, Asok Ray
    Abstract:

    Data-driven fault diagnosis of a complex system such as an Aircraft Gas Turbine engine requires interpretation of multi-sensor information to assure enhanced performance. This paper proposes feature-level sensor information fusion in the framework of symbolic dynamic filtering. This hierarchical approach involves construction of composite patterns consisting of: (i) atomic patterns extracted from single sensor data and (ii) relational patterns that represent the cross-dependencies among different sensor data. The underlying theories are presented along with necessary assumptions and the proposed method is validated on the NASA C-MAPSS simulation model of Aircraft Gas Turbine engines.

Katya Rodriguezvazquez – One of the best experts on this subject based on the ideXlab platform.

  • application of system identification techniques to Aircraft Gas Turbine engines
    Control Engineering Practice, 2001
    Co-Authors: C. Evans, J.p. Norton, I. Pratt, David Rees, P J Fleming, D Hill, Katya Rodriguezvazquez
    Abstract:

    Abstract A variety of system identification techniques are applied to the modelling of Aircraft Gas Turbine dynamics. The motivation behind the study is to improve the efficiency and cost-effectiveness of system identification techniques currently used in the industry. Three system identification approaches are outlined in this paper. They are based upon: multisine testing and frequency-domain identification, time-varying models estimated using extended least squares with optimal smoothing, and multiobjective genetic programming to select model structure.

  • system identification strategies applied to Aircraft Gas Turbine engines
    Annual Reviews in Control, 2000
    Co-Authors: V.y. Arkov, J.p. Norton, C. Evans, I. Pratt, David Rees, P J Fleming, D Hill, Katya Rodriguezvazquez
    Abstract:

    Abstract This paper introduces a study of the derivation of models of Aircraft Gas Turbine dynamics by several system identification approaches. The work was carried out by a consortium of university researchers in close collaboration with Rolls-Royce pic UK. The motivation behind the study is to improve the efficiency and cost-effectiveness of system identification techniques currently used in the industry. Four system identification techniques are outlined in this paper. They are: based upon ambient noise, using multi-sine test signals, extended least squares, and genetic programming to select model structure.

M Rawson – One of the best experts on this subject based on the ideXlab platform.

  • bearing steel microstructures after Aircraft Gas Turbine engine service
    Materials Science and Technology, 2014
    Co-Authors: J R Nygaard, M Rawson, P Danson, H K D H Bhadeshia
    Abstract:

    AbstractThe microstructure of Aircraft Gas Turbine engine bearing steel has been characterised after service in Rolls-Royce Trent™ engines, with the focus on surface condition and the consequences of sliding contact. Carbide populations at the surfaces of rolling elements are found depleted by 30% after 30 000 h engine service. A single ball failure occurred after this period, leading to fatigue spalling that initiated below the contact surface. Comparisons between unused bearing raceways and those that have experienced service revealed that the microstructures resulting from secondary hardening remain remarkably stable. Plastic flow along the direction of rolling is confined to a shallow zone <2 μm beneath the contact surfaces. Transmission electron microscopy has revealed a new deformation mechanism in these bearing steels, in the form of mechanical twinning at interfaces and prior austenite grain boundaries. It is demonstrated that workhardening occurs to a depth of 1 mm in the raceway that has experie...

  • Bearing steel microstructures after Aircraft Gas Turbine engine service
    Materials Science and Technology, 2014
    Co-Authors: J R Nygaard, M Rawson, P Danson, H K D H Bhadeshia
    Abstract:

    AbstractThe microstructure of Aircraft Gas Turbine engine bearing steel has been characterised after service in Rolls-Royce Trent™ engines, with the focus on surface condition and the consequences of sliding contact. Carbide populations at the surfaces of rolling elements are found depleted by 30% after 30 000 h engine service. A single ball failure occurred after this period, leading to fatigue spalling that initiated below the contact surface. Comparisons between unused bearing raceways and those that have experienced service revealed that the microstructures resulting from secondary hardening remain remarkably stable. Plastic flow along the direction of rolling is confined to a shallow zone