Calculation of Local Stresses at the Nozzle Area by using the Finite Element Method

FEM module



Some problems in pressure vessel design cannot or only insufficiently be solved by using the standard equations of the according code. With these problematic cases often an FE calculation is the only way to come to a solution. This calculation is usually quite complex and requires a certain amount of experience with the interpretation of the results.

We offer an integrated FE calculation for several standard problems like nozzles with external loads on cylindrical shells or domed heads. This FE calculation has improved net and graphics options and provides the following calculation options:

Reinforcing pads, oblique nozzles and oblique and tangential nozzles with / without reinforcing pads on cylindrical and spherical shells and  Kloepperboden-type and Korbbogenboden-type (tori-spherical) heads.

The FEM module can be connected with other strength calculation modules of the ATLAS program system. You only have to enter your geometrical data once.


Calculating nozzle loads by means of using the FE method

Fields of application - Overview

Geometrical options

  • Vertical and oblique nozzles on cylindrical shells
  • Vertical and oblique nozzles on spherical shells
  • Vertical nozzles on torispherical and semi-ellipsoidal heads
  • Oblique nozzles on torispherical and semi-ellipsoidal heads
  • Offset / tangential nozzles on cylinders, spheres and domed heads
  • Considering reinforcing pads

Possible loads

  • Forces and moments at nozzle
  • Internal pressure
  • Thermal load
  • Fatigue stress

Calculation and detailed documentation

  • Calculation with FEM (Sparce Solver) with more than 120000 degrees of freedom
  • Calculation with shell elements of finite thickness
  • Free selection of nods and number of elements
  • Stress analysis per AD S4 / ASME VIII-2
  • Fatigue analysis per AD S2 / ASME VIII-2
  • Documentation per AD S4 /ASME VIII-2

Additional features

FEM module: 2.100,- EUR plus VAT

Maintenance (Updates and support) per year 310,-EUR

Fig 1

Offset nozzle on cylinder

Fig. 2

Vertical nozzle with reinforcing pad
on cylindrical shell

Fig. 3

Oblique nozzle on cylinder

Fig. 4

Vertical nozzle on cylindrical shell,

Fig. 5

'Von Mises' stress at nozzle area

Fig. 6

Movement in Y direction

Fig. 7

Tangential nozzle.

Fig. 8

Stresses in tangential nozzle

Fig. 9

Visualization of deformed system „tangential nozzle"

Switching from analytic calculation approaches to the FE method

The statements of the WRC bulletin 107 are based on measurements of several geometrical data of shells and nozzles. It is quite obvious that not all possible configurations could be measured. This statements can only be used restrictively.

This is the reason why LV has integrated a data interface to the  FEM module into the WRC / WRCK module.


The FE calculation is started from the input mask of the according module. This requires no additional action of the user.

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