IAC Acoustics (Austal Ships – Fremantle, Western Australia, Australia)
IAC Acoustics required structural assessment of an existing engine exhaust silencer for a marine project (Austal Ships) which had experienced fatigue cracking and permanent deformation (localised bucking) at various locations. Root cause failure analysis was required applying dead, live (internal pressure) and steady state/transient thermal loads in combination with different restraint conditions to replicate the observed fatigue cracking and localised buckling behaviour at specified locations under service loading conditions.
What we did:
- Performed buckling analysis of the exhaust silencer applying steady state temperature (derived from steady state heat analysis) with different restraint conditions to replicate observed localised buckling behaviour (.e. buckling load factor less than or equal to 1.0).
- Performed quasi-static analysis of exhaust silencer applying transient temperature (derived from transient heat analysis) with design restraint conditions to determine peak stress/strain locations considering nonlinear elastic-plastic) material behaviour.
Outcome:
Avesta Consulting successfully determined the restraint conditions which would most likely cause the observed localised buckling behaviour at steady state design operating temperature and assisted with the development of an alternative exhaust silencer design that would mitigate the premature fatigue cracking issues.
