Detailed fatigue assessment according to EN 13445-3 Clause 18 and AD 2000 S 2

With NextGen it is possible to perform a detailed fatigue calculation for projects according to the EN 13445 and AD 2000 standards.

It is important to underline that in order to perform a detailed fatigue analysis it is essential to have data deriving from a finite element analysis (FEA). This calculation must be performed with a specific software, different from NextGen. Sant'Ambrogio does not offer this type of program nor can it support its choice and use.

For the simplified fatigue analysis, described in the chapters EN 13445 Clause 17 and AD 20000 S 1 there is a dedicated article. The simplified fatigue analysis does not require a supporting FEA.

The calculation is essentially divided into two parts:

• The definition at Item level of the calculation conditions and the number of cycles required
• The definition of one or more analyses relating to specific points of the equipment

In this article, examples relating to EN 13445 are shown, but the same considerations apply to AD 2000. See the respective chapters of the standards for more information regarding the calculation implementations.

Definition of the item properties

The general definition of the calculation takes place in the properties of the Item (File > Item properties > Fatigue). The data must be filled in as follows, enabling the calculation using the appropriate checkbox:

Warning: setting these properties alone does not produce any checks. In the absence of the following steps, no fatigue analysis will be performed.

Detailed fatigue analysis definition

From the ribbon, select the item related to Detailed fatigue assessment:

This item will be added in Desktop view mode, since it does not have a 3D representation.

The data compilation occurs as for a normal component. After defining the name and material, in the Fatigue section the characteristics of the analysis must be defined.

There are different options for choosing the stress extrapolation method. The required values ​​must be taken from the FEA. The program supports the user by indicating at what distance the stress values ​​should be read from the finite element analysis:

The detailed fatigue analysis is a more complex matter than the calculation by formulae of the components available in NextGen. Please refer to the respective standards for further information.

As with a normal 3D component, the detailed fatigue analysis has its own calculation report:

In the summary in the calculation report of the entire device, the detailed analyses are combined with the simplified ones, indicating any errors in red: