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Cold Dwell Fatigue Phenomenon

Cold Dwell Fatigue  Phenomenon

  • The  BEA , France report on A380 engine LP module failure of Air France A380-861 flight on 30/9/17 with Alliance, GP7000 eng highlights it.
  • Earlier Qantas A380 Trent 900 engine had 'uncontained failure' due to different issues on 4th November 2010.
  • Aircraft Gas turbine engine represent complex loading regimes of any thermo-mechanical system & they use Titanium alloy due to their high fatigue strength, low density, and excellent corrosion resistance.
  • However, over 4 decades, it has been observed that titanium alloys suffer from a 'significant failure' mode known as 'cold dwell fatigue', often characterized by 'facet crack nucleation' and subsequent growth under extremes of loading in sub-components such as discs and blades.
  • Due to this, compressor discs in the intermediate pressure section of the engine are among the components deemed to be ‘life-critical’.
  • 'lifetime' reduction resulting from the inclusion of load holds at maximum stress & at ambient temperature<200 °C,  
  • during each loading cycle is termed 'dwell fatigue life debit'.It continues to be a significant OEM concern because its non-destructive testing is hugely costly and it remains a safety-critical issue.


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