CALCS BAS021
FATIGUE LOAD COMBINATIONS

NOTATION

CCcombined case id, component of load group
flgstress, load group, at stress recovery point
fijstress, for unit acceleration factor (i), stress recovery point (j)
Kmiacceleration factor, mean, for acceleration component (i)
Kijacceleration factor, combined case, for unit acceleration (i), stress recovery point (j)
LGload group id
NucNo.unit cases
NlgNo.load groups
SRPstress recovery point

APPLICATION

Fatigue stresses defined by inertial loads acting on a body
Maximum numbers of: Nuc 10, Nuc*Nsrp 1000, Nuc*Ncc 1000

OUTPUT

Max, min, range and mean stresses for each stress cycle group at each stress recovery point

SEE ALSO

BAS005, PROC050, PROC052

THEORY

refs

GUIDANCE

The program is independent of a coordinate system but loads may be components parallel to any chosen axes.
Stress cycle ranges are segregated into groups. Note that the following equality must exist in the input data, Loads/group = Ncc/Nlg
Stress at a point is a function of any number of unit accelerations, for example these may be loads parallel to the structure global x y & z axes.
Any number of unit cases may be defined, program maximun dimension is presently set to ten.
Stresses for combined load cases are derived as,
flgj = f1j.k1j + f2j.k2j + f3j.k3j...+fnj.knj
Stresses are calculated using combined case factors as follows, noting that gravity 1g may be accounted for by setting the appropriate value of km (mean acceleration factor) to 1.00,
fj.(kmj +- kij)

INPUT FORMAT

DAT021title
dataNuc
dataNlg
SRPfu1fu2etc
entertabdelimiteddata
CCK1K2etc
entertabdelimiteddata
ENDDAT

EXAMPLE

Input

DAT021example
3Nuc
2Nlg
SRPfu1fu2fu3
0.0.1.0.
4.7-108.94.5
1002105.757.46237.8
CCK1K2K3
101.002.001
2.0031.010
3.0021.0050
401.017.07
5.0491.1150
6.0341.069.049
ENDDAT

Output

SRPflg1flg2
4max-107.81-96.342
..min-109.99-121.46
..range2.182225.116
..mean-108.9-108.9
1002max58.35276.671
..min56.56838.249
..range1.783438.421
..mean57.4657.46
END021