FEM calculations according to Annex B

The FE method is being used more and more frequently for the constructive design and optimisation of process plants and apparatus.

Analytical calculations are often carried out for the design of standard constructions as well as for a preliminary design of special constructions.

With the help of FE analysis, detail areas and geometries that deviate from the standard can be examined and verified.

In particular, Annex B of the European Standard EN 13445-3 brings advantages in the calculation of complex geometric and stress conditions.

Complex calculation cases

Complex calculations

Calculation standards applied

  • AD 2000 Merkblatt S4
  • EN 13445-3 Annex C
  • ASME VII Div. 2
  • EN 13445-3 Annex B

Distribution of application cases at Lauterbach Verfahrenstechnik GmbH

AD 2000 and EN13445-3 Annex C are the most commonly used calculation standards.

Increasingly, EN13445-3 Annex B is now also being used.

A major difference between AD 2000 and EN13445-3 Annex C or EN13445-3 Annex B is that Annex B does not use stress categorisation.

In stress categorisation, the stresses are divided into local and global ranges and the stress itself is divided into the membrane, bending and peak components.

This is associated with a relatively high effort for complex geometries.


Membrane stress and bending stress

When applying Annex B of EN 13445-3, no stress categorisation has to be carried out. Proof of strength is provided by means of test criteria.

These include:

  • Verification of plastic deformation (GPD-DC)
  • Progressive plastic deformation (PD-DC)
  • Check for instability (I-DC)
  • Check for fatigue (F-DC)
  • Check of the static equilibrium (SE-DC)

All these individual checks must be fulfilled.

Lauterbach Verfahrenstechnik GmbH has developed software tools to carry out these tests within the simulation environment (ANSYS).

The tools allow the permissible load to be determined directly.

Convergence criterion

We offer these calculations as a service.

Lauterbach Verfahrenstechnik GmbH can therefore offer you the entire spectrum of calculation options for FEM simulations. We look forward to your enquiry.

See also:

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