MoVerHu Copyright: © MSE  

MoVerHu - Model-based wear prediction for NANNY



In the context of the maintenance strategy for aviation systems, the "Time Between Overhauls -TBO" indicates the operating time of a system - in this case a helicopter gearbox - until it is overhauled. To determine the TBOs and to select the exchange components for the overhaul, experience-based knowledge is primarily used to determine the relevance of the wear phenomena that occur and their permissible extent. The experience-based determination entails several risks and disadvantages:

  • Experience-based TBO determination is based on knowledge obtained under certain boundary conditions and assumptions. A parametric description of the wear processes and thus a prognosis of the wear progress are not possible with an experience-based approach.
  • Design changes to the gear unit or its components and adapted operating conditions can corrupt the experience gained and the results obtained. Due to the lack of a parametric description of the wear processes, further experience would first have to be gained (experimentally).
  • In order to avoid premature gearbox failure as a result of a component failure, TBOs are planned conservatively in practice and components are replaced before the lifetime is exhausted. This leads to an avoidable restriction of operating time respectively machine availability and prevents a more ecological and resource-saving as well as cost-efficient maintenance strategy. Personal knowledge is difficult to retain if the respective expert leaves the company.

Research objectives

Objective of the MoVerHu project is the development of a methodology for a scientifically based determination of maintenance intervals for helicopter gearboxes. Basis of this methodology is the model-based wear prediction of gearbox components. An experimentally validated prediction of maintenance intervals (TBOs) in hours leads to an increase of machine availability and to a reduction of maintenance costs. Furthermore, the characterization of the occurring wear mechanisms supports the future development of design and tribological optimization measures as well as monitoring systems. The sub-project thus pursues the goal of high-performance and efficient aviation by supporting the paradigm shift from fixed to demand-oriented maintenance activities and the realization of the "Flightpath 2050" goals.

Cooperative project

NANNY - Innovative propulsion and launch systems for the next generation of light to medium-weight helicopters

Project partners

Airbus HelicoptersDeutschland GmbH, ZF Luftfahrttechnik GmbH, Deutsches Zentrum für Luft- und Raumfahrt e.V. (Institut für Aeroelastik, Institut für Aerodynamik und Strömungstechnik), Technische Universität München (Lehrstuhl für Hubschraubertechnologie, Lehrstuhl für Aerodynamik und Strömungsmechanik), Technische Universität Darmstadt (Fachgebiet Strömungslehre und Aerodynamik), Technische Universität Braunschweig (Institut für Strömungsmechanik)

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Funded by

This project is funded by the German Federal Ministry of Economics and Climate Protection.

Project management

Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)

Königswinterer Str. 522-524

53227 Bonn