Lifetime Concepts and Thermomechanics

Components in combustion engines, stationary gas turbines, jet engines, power plant technology and system construction are exposed to high thermal and mechanical loads during operation, often over long operating periods. We support manufacturers and operators of components under thermo-mechanical stress in optimization and the design process to ensure safe operation.

Our core competences are generation, analysis and digital management of material data, development, calibration and validation of models based on sound material mechanics for deformation and lifetime analyses and the development of innovative evaluation concepts and software tools for components under thermomechanical loads.

In current and future research projects, we will be developing our methods and concepts further so that they can be integrated into monitoring systems based on real operating data streams, for example, or used to determine component failure probabilities stochastically. We see our contribution, in particular, in the development of material models which, for example, are able to deal with microstructural features and defects caused by processing and, on that basis, allow predictions to be made about the development of damage and probability of failure.

What we offer

  • Characterization and modeling of metals under thermal and mechanical loads at temperatures ranging from -180 °C to over 1000 °C. This includes, in particular, (C)LCF, TMF, overlapping LCF/HCF and TMF/HCF experiments, high-cycle thermo-shock tests including with overlapping low-cycle fatigue loading and creep fatigue experiments.
  • Completion of crack development tests under isothermal and anti-isothermal conditions with an (alternating current) potential probe and/or optical methods, short crack propagation measurements using the replica technique
  • Completion of warm tension tests, SSRT and pressure tests, relaxation tests and (short-term) creep tests
  • Conception, construction and design calculations for special test devices and test bodies similar to components and completion of those tests.
  • Option for completion of tests under inert gas or high vacuum
  • Explanation of deformation and damage mechanisms in wrought and cast alloys and alloys made by additive manufacturing
  • Adaptation of deformation models for LCF, TMF creep and creep fatigue
  • Adaptation and development of lifetime models for LCF, TMF, creep fatigue and creep
  • Adaptation and development of crack propagation models for LCF, TMF, creep fatigue and creep
  • Provision and development of and training in the application of software tools for lifetime assessment of components
  • Development of knowledge databases for the above experiments and models



Models for cracking, crack propagation and lifetime


Components in combustion engines, thermal power stations and plants and stationary gas and aircraft turbines under thermomechanical fatigue load are usually exposed to larger plastic deformations, at least locally, as a result of which crack formation of a microstructurally short crack on and in microstructure features (e.g. precipitations, grains, phase boundaries) and defects (e.g. production related pores, cavities and discontinuities) usually play a negligible part...


Lifetime concepts and software tools for assessment of the operational behavior of components

The deformation and damage models developed at the Fraunhofer IWM have been incorporated into the ThoMat computational software. The ThoMat computational software can currently be used together with the commercial finite element programs ABAQUS and ANSYS for thermomechanical analysis at component level. Through a modular separation into deformation and...


Model for changing plasticity, cyclical creep and aging


With advanced deformation models, typical material phenomena such as strain hardening, creep, relaxation and strain rate effects can be described in such a way that microstructural changes and their effects on the mechanics can also be taken into consideration. As these changes in the material can occur on different time scales, their integration into the models takes place in a differentiated way. The formation of dense networks of secondary carbides and...


Experimental thermomechanics


Regardless of whether the component design is carried out according to the safe life method or is subject to damage tolerance, for both design philosophies, corresponding material parameters under operational loads are of major importance. In order to fulfil this mission, the »Experimental Thermomechanics« team has an extensive range of testing machines with state-of-the-art experimental technology and a profound expert knowledge in the field of...

Lifetime Concepts, Thermomechanics publications


Contributions to scientific journals, books and conferences as well as dissertations and project reports...