Bulk Data Entry OptiStruct calculates
the ratio of
and prints a WARNING if the frequency interval may not be
fine enough for accurate Fatigue Damage calculation.
Parameter |
Values |
Description |
CHKM0 |
<YES,
NO> |
- YES
- OptiStruct calculates the
ratio of
. 1
- NO (Default)
- OptiStruct does not
calculate the ratio of
. 2
-
Note: WARNING #4403 is not issued
even if the frequency interval is not fine
enough.
Where,
-
- 0th moment (area under the PSD curve) is
calculated using linear interpolation of stress
PSD.
-
- 0th moment is calculated using
logarithmic interpolation of stress PSD with the
frequency interval of min (1Hz, minimum frequency
interval of FRF analysis results).
|
Comments
- If
, a WARNING message is issued indicating that the
frequency interval does not seem fine enough for calculation of accurate
moments. This implies that the frequency interval may not be fine enough for
accurate Fatigue Damage calculation. A way to improve this is to increase number
of frequencies defined on the FREQi entries appropriately.
- If the frequency interval is fine enough, you can
expect
and
to be close to each other. If
is greater than or equal to 95% of
, the
value can become stable with regard to number of
frequencies. If the
value is stable, the subsequent Fatigue Damage
values are also stable.