Author(s)

J Frischbier & J Hausmann

Abstract

Assessment of failure mechanisms of aero engine TMC rotor disks at high rates of strain J. Frischbier1, J. Hausmann2 'MTU Aero Engines GmbH, Munich, Germany 2DLR German Aerospace Center, Institute of Material Research, Cologne, Germany Abstract This paper reports the results of analytical and experimental investigations for the characterization of continuous fiber SiC/Ti composite structures under static, monotonic increasing highspeed and cyclic loading to failure. In overspeed burst spin tests with altogether 3 titanium matrix composite (TMC) bladed rings (blings) it is demonstrated that with all influences of the bling manufacturing process a burst strain close to 0.9% is achievable and reproducable. 1.0% strain to failure is the well known mean value fracture strain for flat laboratory TMC specimens with an almost perfect fiber alignment. In highspeed 4 point bending tests of TMC specimens and in impact tests on cantilever TMC plates strain levels above 10% ( - far beyond the brittle fiber cracking - ) are achieved in the monolithic titanium areas of the structure without any crack detection in the titanium. Finally with fatigue tests of TMC hourglass specimens it is demonstrated that residual prestraining substantially improves the HCF strength of TMC at ambient temperature. 1 Introduction MTU Aero Engines is being investigating the feasibility of silicon carbide fiber reinforced titanium (SiC/Ti) blades and rings for application in military jet engine low pressure compressor blisks. Compared to state of the art integrally bladed rotor d&s (blisk), made of solid monolithic titanium, significant weight savings are predicted without compromising overspeed burst capability or low and high cycle fatigue. For the characterization of the high strength material properties of SiC/Ti MTU Aero Engines is cooperating with specialized material research institutes such as the German Aerospace Center (DLR),

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