Pressure Vessel Under Internal Pressure

A pressure vessel component was assessed to evaluate its structural performance under internal pressurisation. The vessel is designed to safely contain fluids at elevated pressure, making its integrity essential to operational safety and reliability.

Finite element analysis was conducted to examine stress distribution, identify critical regions, and confirm the vessel’s ability to withstand service loading conditions.

Challenge

Pressure vessels are highly sensitive to stress concentrations, particularly around discontinuities such as nozzles, welds, heads, and support attachments. Under internal pressure, these regions can experience elevated membrane and local stresses that may govern the design.

The objectives of the analysis were to:

Evaluate stress distribution under internal pressure.
Identify critical stress concentrations.
Assess the integrity of weld and joint regions.
Confirm the vessel was suitable for the intended operating pressure.

Solution

A detailed finite element model of the pressure vessel was developed, incorporating realistic geometry, boundary conditions, and internal pressure loading to replicate service conditions.

The analysis:

Applied uniform internal pressure to the vessel wall.
Evaluated von Mises stress distribution throughout the component.
Identified peak stress regions at geometric transitions and nozzle intersections.
Assessed the effect of weld details and local reinforcement on structural performance.

The results showed that the highest stresses occurred at stress concentration zones, particularly around openings and transitions, which is consistent with expected pressure vessel behaviour.

Outcome

The analysis provided a clear understanding of how the vessel responds to internal pressure and highlighted areas where design improvements could be beneficial.

Key outcomes included:

Identification of critical stress concentration zones.
Validation of the vessel’s pressure-carrying capability.
Improved understanding of stress distribution across shell and head sections.
Recommendations for geometric refinement and reinforcement where required.

Suggested improvements included increasing local thickness in high-stress regions, refining nozzle reinforcement, and reviewing weld geometry to reduce peak stresses and improve fatigue performance.

Testimonial

“ The analysis gave us confidence that the vessel could safely withstand the applied pressure and clearly showed where the design needed closer attention before manufacture.”

— Senior Mechanical Engineer