Flow-Induced Dynamic Stress and Fatigue Analysis of an Industrial Manifold Assembly
Location
Structure Type
Software Used
Western Canada (Undisclosed Facility)
Tempering Air Manifold
Abaqus, STAR-CCM+ (CFD), Python (FFT)
Objective
To evaluate the dynamic structural response and fatigue life of a tempering air manifold system subjected to internal flow fluctuations. This assessment combined computational fluid dynamics (CFD) and finite element analysis (FEA) to determine pressure-induced stress behavior and ensure long-term structural integrity in line with ASME Section VIII, Division 2 criteria.
Results from CFD Analysis: Pressure vs Frequency
Pressure from FEA Analysis: Stress vs Frequency
Challenges
Complex geometry requiring separation into three independent assemblies due to expansion joints.
Need to convert unsteady pressure signals from CFD into frequency domain using FFT for dynamic FEA input.
Requirement to evaluate modal behavior and dynamic amplification across varying support conditions.
Solution
CFD simulations were performed to capture static and fluctuating pressures across the duct system. Transient pressure data were converted to the frequency domain using FFT and applied in Abaqus for dynamic stress analysis. Modal, static, and dynamic analyses were conducted to assess structural behavior. Combined stresses were evaluated against ASME limits, and fatigue life was estimated using weld strength reduction factors, confirming the structure's suitability for cyclic operation.
Result
The comprehensive FEA revealed that all major components of the TA Manifold are structurally sound under both static and flow-induced dynamic loads. Fatigue life projections confirm that the assemblies meet operational demands for expected startup/shutdown cycles. Recommendations were made for minor support frame enhancements.
