IEC

Random Response Fatigue is evaluated at each global direction for each weld location.

The implementation process is shown in Figure 1.

Figure 1.

(1)

$$D_{direction}=\sum \frac{n}{N}$$

• $D_{direction}$ = Total damage from 1 $\sigma$ , 2 $\sigma$ , and 3 $\sigma$ in each direction.
• $n$ = Total exposure time ( $n_{{}_{\sigma }}$ ).
• $N$ = Fatigue Life (maximum number of cycles of a particular stress amplitude $\sigma$ for the material prior to failure) from the Material SN curve.

Fatigue Material

SN materials for Weld locations in the Points context are created/selected from the Material context.

To assign materials to parts, right-click the material in the My Material tab and select Add to Assign Material List from the context menu. From the Points context, select the appropriate weldline and enable the Evaluate checkbox. In the Location section, select the appropriate material in the Material - Transverse column. Once the selection is made, right-click the material and select Apply current value to all Locations from the context menu.

Both Slope-intcept,1-seg and Slope-intcept,2-seg are supported.

Weld Templates are supported for Material assignment to weld locations.

Query Report

Preferences > Save Rainflow Data can be used to query elements for viewing Report.

Restriction:

• Supports only OptiStruct model/results.
• Supports only shell element evaluation (via element stress).
• Report is only available on requesting Rainflow output via Preferences.
• Stress Query is supported only for Nominal Approach.