IAC Acoustics (UGL – New South Wales, Australia)
IAC Acoustics required thermal-structural analysis, fatigue assessment, exhaust flow analysis and design optimisation/modification of a diesel locomotive muffler. Fluid flow analysis, thermal-structural assessment and fatigue analysis was required to develop and verify the locomotive muffler design considered permanent, imposed (gas flow induced drag, roof platform), internal pressure, thermal, shock, vibration and lifting loads.
What we did:
- Performed steady state thermal-fluid flow CFD analysis to determine turbulent gas flow characteristics including drag induced pressure losses and wake turbulence induced cyclic lateral pressures (on splitter components).
- Performed steady state heat and static structural FEA applying permanent, imposed, internal pressure, thermal, shock, vibration and lifting loads.
- Determined peak stresses in locomotive muffler components and verified design compliance with allowable stress requirements.
- Performed frequency domain fatigue analysis of locomotive muffler components considering vibration loads (applying the Dirlik solution method to determine stress range probability density functions from PSD frequency data) with application of uniform material law (UML) specified fatigue strength values to calculate time based equivalent fatigue damage, Palmgren-Miner rule based fatigue damage accumulation, and specified operating hours for locomotive muffler service life determination.
Outcome:
Avesta Consulting verified the structural integrity and fatigue life of the locomotive muffler and provided appropriate design modifications to achieve the required minimum operating hours.
