FE analysis of a notched bar under thermomechanical fatigue using a unified viscoplasticity model

D.W.J. Tanner, W. Sun, T.H. Hyde

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

5 Citations (Scopus)

Abstract

The combination of cyclic (due to startup and shutdown) thermal and mechanical stresses can result in thermomechanical fatigue (TMF) failures in aero engine and power plant components (for example).

Unified viscoplastic constitutive models have been successfully used to describe the macroscopic behaviour of materials where both rate-independent and rate-dependent effects occur simultaneously, e.g. high temperature cyclic loading. One of the most well known physical-phenomelogical models using state variables, developed in the framework of the thermodynamics of irreversible processes, was formulated by JL Chaboche. The Chaboche model includes combined nonlinear isotropic and kinematic hardening, with a viscoplastic flow rule for time-dependent effects, including creep.

This paper uses Z-mat software to implement the multiaxial form of the Chaboche constitutive equations into the ABAQUS finite element (FE) code. The evolution of complex stress and strain fields within a grade P91 steel notched bar specimen are investigated in detail for different TMF loading conditions. The results of this work can be used to determine suitable test conditions for notched specimens by providing predictions of the stress-strain history local to the notch. In future, such tests will be used along with the FE analyses to develop and validate multiaxial TMF lifing models.
Original languageEnglish
Title of host publication11th International Conference on the Mechanical Behavior of Materials (ICM11)
Place of PublicationLake Como, Italy
Publication statusPublished - 2011
Event11th International Conference on the Mechanical Behavior of Materials (ICM11) - Como, Italy
Duration: 5 Jun 20119 Jun 2011

Conference

Conference11th International Conference on the Mechanical Behavior of Materials (ICM11)
CountryItaly
CityComo
Period5/06/119/06/11

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