This data record may be omitted, in which case the default values shown below will be used.
2 5 7 11 31 41 51 61
- --- -- ---- ... ---------- ---------- ---------- ----------
|X|XXX| |TFAT| | | | | |
- --- -- ---- ... ---------- ---------- ---------- ----------
| | | | | |
| | |---------------------------------
| | |
| | |_(1) 4 Fatigue parameters( 4E10.0)
| |
| |_Compulsory Data Record Keyword (A4)
|
|_Optional User Identifier (A2)
(1) The four fatigue parameters are:
Reserved (leave blank)
Stress concentration factor (default value 1.24)
SN Curve intercept coefficient (default value 1.3367E24) (Units are consistent with stress in kN/m2)
SN Curve slope m (default value 3.5)
Fatigue life (days) = 1/(damage per day)
The formula used to calculate the fatigue life is
where
R(i) = stress range (computed from rainflow count of time history stresses)
N(i) = number of cycles per day for this stress range (from probability distribution by rainflow count)
SCF = stress concentration factor
m = SN curve slope
A = SN curve intercept coefficient
NBIN = number of bins in the stress probability distribution