Project overview

About the project

DevTMF focuses on Development of Experimental Techniques and Predictive Tools to Characterise Thermo-Mechanical Fatigue Behaviour and Damage Mechanisms of two nickel-base superalloys.

In recent years, there has been an increased awareness of the environmental impact of air travel. Therefore, of vital strategic importance to the European aviation industry is to reduce aero engine emissions, which is driven by the EU regulations along with industrial competition. Low emissions, improved fuel efficiency and advanced temperature capability are a major focus of the Rolls-Royce on-going innovative engine demonstrator programmes, Advance and UltraFanTM, for middle of market, corporate and regional engines. As would be expected, a significant portion of these improvements will be expected to come from engine designers in term of gas turbine efficiency. Increases in efficiency of the gas turbine will usually be achieved in one of two ways; either weight reductions or increases in temperature, resulting from the fuel being burnt at temperatures approaching the stoichiometric value. In either case, it is clear that there will be a significant impact on the materials used. The modern criteria for such materials include a high temperature fatigue and creep capability with suitable environmental and corrosion resistant properties. These ever increasing temperatures to improve efficiency whilst reducing fuel consumption and environmental impact leads to harsh alternating mechanical and thermal loads during start up, take-off, descent and shut down operations. Such situations can cause local stresses to peak at temperatures far below the flight cycle maximum and can lead to the nucleation and propagation of cracks through to failure, a phenomenon which is known as thermo-mechanical fatigue (TMF).

The objectives of DevTMF is therefore to characterise TMF behaviour of alloys of interest to allow for more accurate prediction of design lives of present and future gas turbine components. The ultimate goal is to enable further increase of operation and service life, which will subsequently provide environmental and economic benefits to the European gas turbine industry and Europe.

The DevTMF roadmap is presented figure below in more details.

DevTMF roadmap

Robust, statistical assessed and easily calibrated predictive TMF crack initiation and propagation models consistent with the damage mechanisms and sensitive to the fatigue damage process for life assessment of critical components developed in DevTMF will provide accurate extrapolations from a known set of results.

Work plan

The project is a 48-month project and is divided into 3 work packages, out of which 2 are dedicated to technical activities:

  • WP1 is dedicated to the project management and dissemination/exploitation activities, and is managed by LiU with the help from other partners.
  • WP2 is focused on experimental activities and it is lead by SU. It also includes supporting activities such as material procurement and specimen machining. It will generate TMF CI and CP data for the modelling and validation in WP3. In parallel with the material procurement activities, the WP will do a literature review of the state of-the-art of the TMF CI and CP testing and modelling work. It will also begin directly with the characterisation of thermal gradients and bench-marking of the both test methods. It also includes characterisation work to understand damage mechanisms in the alloy/alloys under the
    TMF conditions.
  • WP3 covers modelling activities lead by UNOTT. At the start of the project, this WP will focus on to define parameters and conditions for the experimental activities (both TMF CI and CP). This is a fundamental WP that will also feed into WP2. It also includes validation of the prediction models by using component TMF relevant cycles.

DevTMF work packages and their interdependence