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Comportement mécanique à haute température d'un composite alumine/alumine

Abstract : The use of oxide/oxide composites is envisaged in the design of new generation aeronautical engines. These materials were studied at room temperature or at high temperature (>1100°C). The mechanical behaviour of the material developed at ONERA was studied in this case from room temperature to 1300°C. The characterisation carried out in traction allowed us to distinguish two very different types of behaviour which overlap at a temperature of about 800 °C. At low temperatures, the material's behaviour is elastic and damaging. Above this temperature, a viscous behaviour progressively appears, leading to anelastic deformations of several percent. Compared to the results obtained in tension at low temperatures, the behaviour in bending revealed a dissymmetry between tension and compression: unlike tension, compression does not cause damage, the behaviour remaining very close to the elastic domain observed in tension. Bending tests carried out in a SEM have made it possible to highlight this dissymmetry by revealing damage in tension starting at 150 MPa. The damageable behaviour was described by a law inspired by the family of ODM models developed at ONERA. An adaptation of the law was necessary to account for the effect of temperature. The parameters of the behaviour law in tension were identified. A finite element calculation of the bending tests validated the proposed model. The introduction of the damage constitutive equation in the classical laminate theory (CLT), commonly used for the study of complex composite laminates, led to a modelling of the material response in bending. These simulations were validated by comparison with experimental results. A statistical analysis of the bending strength was conducted at room temperature and at 800°C. The Weibull modulus, which characterises the dispersion, is not affected by temperature. Finally, the creep of the material was studied in tension and 4-point bending. A very strong predominance of stationary creep was observed. The creep kinetics in tension was identified by a Norton law coupled with an Arrhenius term. In parallel, a model based on the CLT was proposed for the modelling of viscous behaviour.
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Submitted on : Tuesday, March 15, 2022 - 8:39:08 AM
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  • HAL Id : tel-03608646, version 1

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Antoine Débarre. Comportement mécanique à haute température d'un composite alumine/alumine. Mécanique des matériaux [physics.class-ph]. Université Paris sciences et lettres, 2021. Français. ⟨NNT : 2021UPSLM048⟩. ⟨tel-03608646⟩

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