A STOCHASTIC RELIABILITY MODEL FOR APPLICATION IN A MULTIDISCIPLINARY OPTIMIZATION OF A LOW PRESSURE TURBINE BLADE MADE OF TITANIUM ALUMINIDE

Authors

  • CHRISTIAN DRESBACH GERMAN AEROSPACE CENTER INSTITUTE FOR MATERIALS RESEARCH
  • THOMAS BECKER
  • STEFAN REH
  • JANINE WISCHEK
  • SASCHA ZUR
  • CLEMENS BUSKE
  • THOMAS SCHMIDT
  • RUEDIGER TIEFERS

Keywords:

SIZE EFFECT, WEAKEST LINK, INVESTMENT CASTING.

Abstract

CURRENTLY, THERE ARE A LOT OF RESEARCH ACTIVITIES DEALING WITH TITANI-UM ALUMINIDE (TIAL) AS A NEW MATERIAL FOR LOW PRESSURE TURBINE (LPT) BLADES. EVEN THOUGH THE SCATTER IN MECHANICAL PROPERTIES OF SUCH AN INTERMETALLIC ALLOY IS MORE DISTINCTIVE AS IN CONVENTIONAL METALLIC ALLOYS, STOCHASTIC INVESTIGATIONS ON TIAL ARE VERY RARE. FOR THIS REASON, WE ANALYZED THE SCATTER IN STATIC AND DYNAMIC ME-CHANICAL PROPERTIES OF THE CAST ALLOY TI-48AL-2CR-2NB. IT WAS FOUND THAT THIS ALLOY SHOWS A SIZE EFFECT IN STRENGTH WHICH IS LESS PRONOUNCED THAN THE SIZE EFFECT OF BRITTLE MATERIALS. A WEAKEST-LINK APPROACH IS ENHANCED FOR DESCRIBING A SCALABLE SIZE EFFECT UNDER MULTIAXIAL STRESS STATES AND IMPLEMENTED IN A POSTPROCESSING TOOL FOR RELIABILITY ANALYSIS OF REAL COMPONENTS. THE DEVELOPED RELIABIL-ITY TOOL WAS INTEGRATED INTO A MULTIDISCIPLINARY OPTIMIZATION OF THE GEOMETRY OF A LPT BLADE. SOME PROCESSES OF THE OPTIMIZATION WERE DISTRIBUTED IN A WIDE AREA NETWORK, SO THAT SPECIALIZED TOOLS FOR EACH DISCIPLINE COULD BE EMPLOYED. THE OPTIMIZATION RESULTS SHOW, THAT IT IS POSSIBLE TO INCREASE THE AERODYNAMIC EFFICIENCY AND THE STRUCTURAL MECHANICS RELIABILITY AT THE SAME TIME, WHILE ENSURING THE BLADE CAN BE MANUFACTURED IN AN INVESTMENT CASTING PROCESS.

Published

2016-06-27

Issue

Section

ACE-X 2015