SN Graph Does not match inputted Values in Designlife Glyphworks

[thecadguy]

Dear All,

I am trying to develop a new SN curve within Ncode Designlife using the material manager. Using the fatigue theory guide I generate all the parameters for aluminum uisng the equations given and the UTS of the material. I chart this in excel and everything looks good. The B1 value is good as well as the Stress level at 10^3 cycle and 5^8 cycles.

When I go to enter the material in the material manager all is inputted with no problems. When I go to the graph the intercept at Cycle 1 is correct however the stress values at 10^3 cycle and 5^8 cycles are much higher then the calculated values.

For the life of me I can not figure out what is going on. I would rather import the actual curve but can only find the parameter way to generate the curve. I would feel much better with the results of the graph matched the actual values plugged in.

Values USed

UTS 315.000

SRI1 745.807
S1 220.500
S2 81.270
B1 -0.0761
NC1 5E+08
B2 -0.040
SE 0.100
RR -1.000

UTS Cor 630


Graph shows 155 Mpa for S2 when it should be 82 Mpa. S1 should be 220 graph shows 425.

Any feedback would be appreciated.

The CAD Guy