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Caractérisation thermomécanique et détermination de lois de comportement de revêtements abradables de compresseurs basse et haute pression de turboréacteurs pour de larges gammes de vitesses de déformation et de températures

Abstract : Abradables coatings used to minimize inter-stage leakages in aircraft engines, take part in severe interaction with blades. Concerning the compressor stages, those interactions take place in environments where temperatures go up to 350°C and 800°C respectively for low-pressure and high-pressure compressors (LPC and HPC). High-speed rotation of blades leads to complex dynamic solicitation within abradable material combining compression, tension, and shear components. The thermomechanical behavior knowledge of those materials under extreme solicitations is a key point in the understanding of blades-abradables interaction and their numerical simulation. This work aims to characterize the thermomechanical behavior under representative conditions of two abradable materials, an AlSi-PE from the LPC and a CoNiCrAlY-hBN from the HPC. The experimental bench of the Split Hopkinson Pressure Bar allowed investigation in compression for strain-rates up to 103 s-1 and for temperatures up to 350°C and 800°C depending on the abradable material. Quasi-static tests in temperature completed this characterization of the compression response. In addition, dynamic shear tests and quasi-static and dynamic Brazilian tests were performed on the AlSi-PE abradable. This thermomechanical behavior characterization was able thanks to specimens extracted from thick abradable coatings. The AlSi-PE abradable was able to highly deform under compression loading. A sensibility to the strain-rate and the temperature was identified. The CoNiCrAlY-hBN abradable showed a fragile behavior with no sensibility to the temperature but a sensibility to strain-rate. The thermomechanical behavior in compression of both abradable, from 10-3 s-1 to 103 s-1 and temperatures were modeled with bilinears behavior laws. In addition, a plastic model based on the Johnson-Cook law is introduced for the AlSi-PE abradable.
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https://hal.univ-lorraine.fr/tel-02877184
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Submitted on : Monday, June 22, 2020 - 10:15:22 AM
Last modification on : Friday, July 17, 2020 - 2:58:25 PM

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  • HAL Id : tel-02877184, version 1

Citation

Stéphane Skiba. Caractérisation thermomécanique et détermination de lois de comportement de revêtements abradables de compresseurs basse et haute pression de turboréacteurs pour de larges gammes de vitesses de déformation et de températures. Mécanique des matériaux [physics.class-ph]. Université de Lorraine, 2019. Français. ⟨NNT : 2019LORR0324⟩. ⟨tel-02877184⟩

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