Identification of viscoplastic constitutive and creep-fatigue damage coefficients to use in abaqus automotive structural calculations with the zmat library
Résumé
Complex constitutive equations are needed to accurately predict the failure of high temperature components such as car diesel engine cylinder heads or exhaust manifolds. They may have to take into account the evolution of the material behavior relating to aging or phase changes, which strongly affect the stress-strain history and lifetime predictions.
Such advanced viscoplastic material models are available for ABAQUS users by means of Zmat library, which implements a series of constitutive equations and can be seen by ABAQUS as a huge UMAT subroutine, and also offers numerical tools for making the development of new models easier. Creep-fatigue damage models are also available in a companion code, which can be used as a post-processor with ABAQUS.
However, one key point for the industrial use of such methods is the identification of material coefficients, which can still be cumbersome considering the large number of parameters involved. The purpose of this paper is to present identification tools called Zsim and Zopt that can be a great help in this task. The capabilities of this software are demonstrated by the full identification of the cyclic viscoplastic properties of a typical engine material and its creep-fatigue behavior.
An application to the ABAQUS calculation of a RENAULT SA car engine component will be presented with the aim to derive number of cycles to failure in the low cycle thermomechanical fatigue regime.
Domaines
Sciences de l'ingénieur [physics]
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Identification_of_viscoplastic_constitutive_and_cr.pdf (897.75 Ko)
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