Uniaxial Fatigue Analysis, using S-N (stress-life) approach for predicting the life (number of loading cycles) of
a structure under cyclical loading may be performed by using HyperLife.
Random Response Fatigue is evaluated at each global direction for each element of the
selected Parts.
The implementation process is shown in Figure 1.
(1)
= Total damage from 1, 2, and 3 in each direction.
= Total exposure time ().
= Fatigue Life (maximum number of cycles of
a particular stress amplitude for the material prior to failure) from the
Material SN curve.
Fatigue Material
SN materials for Parts/Components 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.
Navigate to the Assign Material Data tab, enable the desired part, and
select the appropriate material in the Material column.
Both Slope-intcept,1-seg and Slope-intcept,2-seg are supported.
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.
Table 1. Assign Material Parameters
Parameter
Description
Material
Material assigned to the part.
Material list for selection
is created by adding Materials to the Assign Material list
from Material Db, My Material, or HM Material
tabs.
Material Units
Unit of the assigned material.
Plot
Stress Life plot of the assigned material.
FL
Fatigue Limit of the assigned material.
Output
Cumulative Damage in XX, YY, and ZZ across all events and total across all
three directions per layer.