danle89

Daniel Leidermark

Associate Professor

Mainly, my research is focused on the behaviour of single-crystal nickel-base superalloys. Investigation is centered around the mechanical behaviour, through experimental observation and modelling of these. I teach within solid mechanic courses.

High temperature mechanics – a constitutive behaviour approach to fatigue issues

The trend in the global electricity generation is changing towards a state where green energy, e.g. hydro, wind or solar power, will become the largest power source. With this increasing supply from green energy the need to be able to balance the power output is fundamental. A way to accomplish this is to use gas turbines as the bridge to green energy. 

These can be taken online or offline in a matter of minutes to produce power, a suitable balancer to the green energy sources. The rapid changes in energy production set high reliability on the gas turbines components. These changes introduce a cyclic exposure of the components which leads to thermomechanical fatigue load conditions. 

At peak loading the components will be subjected to high temperature in combination with high mechanical load, hence exposed to creep/stress relaxation. 

The increased usage of gas turbines on the energy market sets high demands on the environmental impact and efficiency, meaning that better prediction methods and more realistic behaviour of the materials are needed in the simulations during the design phase. 

Single-crystal nickel-base superalloys

The major class of materials used for the first stage turbine blades is single-crystal nickel-base superalloys, due to their excellent high temperature properties. See Fig. 1 for a typical microstructure image of a single-crystal superalloy. These blades are manufactured through investment casting, a perfectly aligned specimen is never achieved during this process, hence misalignments in crystal orientation need to be accounted for, see Fig. 2. 

However, the anomalous elastic and inelastic material behaviour of single-crystal nickel-base superalloys makes the evaluation/design process rather complex, see Fig. 3. Hence, insufficient knowledge of the material behaviour often leads to the use of large safety factors that leads to conservative designs, which in turn render loss in performance and efficiency.

Visualisation of research
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Fig. 1: Microstructure of a single-crystal nickel-base superalloy.
Fig. 2: Definition of misalignment in crystal orientation of the specimen.
Fig. 2: Definition of misalignment in crystal orientation of the specimen.
Fig. 3: Monotonic tension and compression tests of a single-crystal nickel-base superalloy.
Fig. 3: Monotonic tension and compression tests of a single-crystal nickel-base superalloy.

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CV

  • PhD Solid Mechanics, Linköping University, Sweden 2011
  • Lic. Solid Mechanics, Linköping University, Sweden 2010
  • MSc Mechanical Engineering, Linköping University, Sweden 2008
  • BSc Mechanical Engineering, Växjö University, Sweden 2004


Publications

You can find publications related to Daniel Leidermarks work at Scopus.

Research interest

  • High temperature mechanics
  • Constitutive modelling
  • Single-crystal superalloys
  • Crack initiation and propagation
  • Thermomechanical fatigue

Teaching

  • Solid Mechanics, basic course (TMMI17)
  • Advanced material and computational mechanics (TMHL19)