On the Simulation of Large Viscoplastic Structures under Anisothermal Cyclic Loadings

Abstract

The optimal design of parts submitted to thermomechanical loadings is a key issue for the safety and quality assessments of structures. In this context, the present paper discusses the choice of a behavior model and the determination of its parameters. For cast iron and aluminum alloy applications, two constitutive laws are compared : one is based on a classical unified viscoplastic model and the other is based on a two layer plastic-viscous rheological model. The following discussion shows that the use of anisothermal experiments is very important for the identification of material parameters and that simple models can be successfully applied for the predictive lifetime assessments of large 3D structures.

A computational approach to thermomechanical fatigue

“…3, which displays the variation of the standard yield limit R c at 0.2%. A discussion of the identification procedure and its implication on the final computational result is presented by Verger et al in [28].…”

Détermination de la réponse asymptotique d'une structure anélastique sous chargement thermomécanique cyclique

“…Pour illustrer cette méthode, nous présentons l'exemple d'une structure ayant une géométrie et un chargement thermique représentatif de la zone de la culasse la plus sensible à la fatigue thermomécanique. Le modèle de comportement utilisé pour simuler le matériau est un modèle élastoviscoplastique dont les détails de l'implémentation numériques sont données dans [10]. Cette pièce est soumise à un chargement thermique cyclique à fort gradient.…”

“…An illustration of this method is given on the example of a structure which is representative of the part of a cylinder head, most sensitive thermomechanical fatigue. The material used is elastoviscoplastic [10]. The structure is subjected to a thermal loading with strong gradient.…”