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Determination of stable and robust material properties for the assessment of thermomechanically loaded components of rocket engines with viscoplastic constitutive equations

  • Components of rocket engines as actively cooled combustion chambers must withstand high pressure as well as severe and complex thermal transients. While the thermal transients result in temperature gradients and, thus, in constraint thermal strains, the pressure load induces mean stresses. To assess the mechanical behaviour of such components during design via finite-element calculations,Components of rocket engines as actively cooled combustion chambers must withstand high pressure as well as severe and complex thermal transients. While the thermal transients result in temperature gradients and, thus, in constraint thermal strains, the pressure load induces mean stresses. To assess the mechanical behaviour of such components during design via finite-element calculations, constitutive models are necessary that describe the time- and temperature-dependent plasticity of the material appropriately. Advanced models account for viscoplastic deformations including isotropic and kinematic hardening, recovery and ratcheting. However, the models contain a relatively large number of temperature-dependent material properties that must be determined on the basis of data of material tests. The determination of the properties is a non-trivial task because it is not clear which loading history must be applied in the tests for a certain material to obtain stable and robust (i.e. objective) material properties. Consequently, the determined properties are depending on the underlying loading history in the tests as well as on the experience and valuation of the person that determined the properties. This results in uncertainties during the assessment of the components that must be faced with conservative designs leading to negative consequences in terms of mass and costs. It is the aim of this work funded by the European Space Agency ESA to derive a procedure to determine stable and robust material properties of an advanced viscoplastic constitutive model for aerospace materials. To this end, a special loading history is applied in isothermal material tests conducted with copper at different temperatures in the temperature range from 300 to 700 K. To determine the material properties and to assess stability and robustness methods for numerical optimization as well as analytical and statistical methods are used. The determined material properties are validated on the basis of results of thermomechanical material tests also conducted in the temperature range from 300 to 700 K.show moreshow less

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Metadaten
Document Type:Conference Proceeding
Conference Type:Konferenzartikel
Zitierlink: https://opus.hs-offenburg.de/2141
Bibliografische Angaben
Title (English):Determination of stable and robust material properties for the assessment of thermomechanically loaded components of rocket engines with viscoplastic constitutive equations
Conference:14th European Conference on Spacecraft Structures, Materials and Environmental Testing (ECSSMET), 27-30 September 2016, Toulouse, France
Author:Ivan RekunStaff Member, Thomas SeifertStaff MemberORCiDGND, Roland Jörg
Year of Publication:2016
Page Number:15
Parent Title (English):The 14th European Conference on Spacecraft Structures, Materials and Environmental Testing (ECSSMET)
URL:https://extranet.insight-outside.fr/upload/compte748/Base/inscriptions_projets/fichier2/57435-fichier2.pdf
Language:English
Inhaltliche Informationen
Institutes:Fakultät Elektrotechnik und Informationstechnik (E+I) (bis 03/2019)
Institutes:Bibliografie
Tag:smart grid
Formale Angaben
Open Access: Open Access 
Licence (German):License LogoUrheberrechtlich geschützt