The engineering task
A nozzle on a spherical vessel or spherical head is loaded by piping forces and moments in addition to internal pressure. Its local stress distribution differs substantially from that of a cylindrical shell. Large openings, reinforcement pads and short distances to welds may limit simplified solutions.
The assessment requires a local coordinate system on the spherical surface and clearly defined load combinations. Analytical EN or WRC results serve as the primary check or as a reference for supplementary FEA.
Required design data
- Sphere radius, thickness and nozzle geometry
- Pressure and piping load sets with signs
- Materials and temperature
- Distances to welds, openings and supports
Technical solution approach
Check geometric limits
Compare dimensional ratios and clearances with the methods' applicability limits.
Transform local loads
Convert global piping loads into meridional, tangential and radial components.
Perform the EN check
Calculate local shell effects to DIN EN 13445-3 for relevant load cases.
Compare the WRC result
Use an independent WRC approach for plausibility and to identify sensitive load components.
Decide on FEA
Specify three-dimensional FEA where limits, large openings or strong neighbouring interactions require it.
Expected deliverables
Suitable SOL ALPHA modules
The modules form a technically plausible toolchain. Their final selection and sequence will be confirmed during the later calculation against the applicable code and project conditions.