Vorgehensweise zur Implementierung von Werkstoffmodellen in die Lebensdauerbewertung von thermo-mechanisch beanspruchten Komponenten

Translated title of the contribution: Approach to implement material models for the lifetime prediction of thermo-mechanical loaded components

Martin Fortin

Research output: ThesisDiploma Thesis

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Abstract

The present thesis deals with the verification of methods for the evaluation of the lifetime as well as parameterisation and implementation of material models for investigating the loading situation of thermo-mechanically loaded components. An outline of material models and their possibility for the use concerning an implementation in a simulation of thermo-mechanical loaded components is given. Therefore different models for the characterization of the materials response in the commercial finite element solver Abaqus have been studied regarding to the possibility of their use in simulation. In the course of this work a routine was developed for the creation of material parameters for the nonlinear isotropic/kinematic hardening model from thermo-mechanical fatigue (TMF) test data. The parameterisation of these dimensions is based on stress-strain curves measured in an attempt whereas determines are calculated with the help of an unconstraint non-linear optimisation in Matlab. With the selected material model, it is possible to simulate the elaborate loading situations in geometrically complex components where a combination of thermal and mechanical loads is applied. For a qualitative verification of the material parameters, calculated by the developed routine, a simulation model was generated and the found parameters were integrated into this. The implementation of the material model was done by an user subroutine which selects the suitable parameters to describe the material behaviour depending on the loading situation, constraint factor and temperature. This process enables the determination of the loading situation in the structure considering temperature, constraint factor and loading direction. The stress-strain distribution determined in the simulation is used as a basis for the lifetime evaluation. Further more, different methods for the lifetime prediction are compared with each other and their quality is evaluated. The present work gives an overview of the most essential methods for the lifetime assessment of thermal and mechanically loaded components and shows the possibility of adapting and implementing a material model in a conventional FE-solver.
Translated title of the contributionApproach to implement material models for the lifetime prediction of thermo-mechanical loaded components
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Eichlseder, Wilfried, Supervisor (internal)
  • Winter, Gerhard, Co-Supervisor (internal)
Award date18 Dec 2009
Publication statusPublished - 2009

Bibliographical note

embargoed until null

Keywords

  • thermo mechanical fatigue material models user subroutine lifetime prediction

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