P. Gomez, Centre d'Essais Aéronautique de Toulouse (CEAT), Balma Cedex, France
The aerospace industry has severe technical and economical requirements needed to continuously improve performance. Therefore the industrials are always looking for lighter weight and, for aeroengines, higher thrust and better efficiency.
Metal matrix composites (MMCs) are a possible attractive issue to this fact because of their specific mechanical properties in comparison with the monolithic alloys currently used. MMCs allow imagining breakthrough technologies.
The blings - bladed rings - constitute one of these possible breakthrough technologies. The blings are MMC rings which could replace the compressor and turbine disks in turbojet engines. This design would lead to an important weight reduction of the engine rotating parts and would increase its compactness.
The EPICUR program is targeting the development of a Titanium matrix composite TiMMC obtained by the Snecma’s EGV coating process; the setting-up of a sizing procedure; the production of real scale bling (i.e. 400 mm diameter), and the spinning test of the parts.
Snecma has already produced a TiMMC composed of a Ti6242 titanium alloy matrix reinforced with the SCS-6 silicon carbide fibre. Several blings scale ½ (i.e. 200 mm diameter) have been compacted by Hot Isostatic Pressure HIP among which one is stemming from the EGV process.
ONERA has performed two kinds of calculations to satisfy the requirements of the bling sizing. The first one attempts to predict the static speed burst. This finite element (FE) analysis is based on anisotropic non linear constitutive equations (plasticity coupled to damage) using a stiffer behavior in the reinforced direction and poor mechanical properties in the transverse ones. The second calculation evaluates the lifetime of the blings from the post-processing of the results obtained by the FE calculation. ONERA’s fatigue damage model is stress based and is able to take into account the load multiaxiality and the material anisotropy.
Summary: The aeronautic is a field where technical and economical requirements are severe in order to improve continuously the performance. Therefore the industrials are always looking for lighter weight and, for aeroengines, higher thrust and better efficiency.
Metal matrix composites (MMCs) are a possible attractive issue to this fact because of their specific mechanical properties in comparison with the monolithic alloys currently used. MMCs allow imagining breakthrough technologies.
The blings - bladed rings - constitute one of these possible breakthrough technologies. The blings are MMC rings which could replace the compressor and turbine disks in turbojet engines. This design would lead to an important weight reduction of the engine rotating parts and would increase its compactness.
The EPICUR program is targeting :
• the development of a Titanium matrix composite TiMMC obtained by the Snecma’s EGV coating process,
• the setting-up of a sizing procedure,
• the production of real scale bling (i.e. 400 mm diameter),
• and the spinning test of the parts.
Snecma has already produced a TiMMC composed of a Ti6242 titanium alloy matrix reinforced with the SCS-6 silicon carbide fibre. Several blings scale ½ (i.e. 200 mm diameter) have been compacted by Hot Isostatic Pressure HIP among which one is stemming from the EGV process.
ONERA has performed two kinds of calculations to satisfy the requirements of the bling sizing. The first one attempts to predict the static speed burst. This finite element (FE) analysis is based on anisotropic non linear constitutive equations (plasticity coupled to damage) using a stiffer behavior in the reinforced direction and poor mechanical properties in the transverse ones.
The second calculation evaluates the lifetime of the blings from the post-processing of the results obtained by the FE calculation. ONERA’s fatigue damage model is stress based and is able to take into account the load multiaxiality and the material anisotropy.
At the moment, the CEAT has tested materials coupons of TiMMC and half a dozen of Snecma blings (scale ½) on its fatigue disk spinning test facilities. The results show a good accordance between the models (behavior and fatigue) and confirm the potential of the TiMMC bling.
