1. Choose r·t^-1 and d·D^-1
Following conditions need to be fulfilled:

r·t-1 = 0.03 - 10

d·D-1 = 0.4 - 0.98

If you only want to determine the SCF for single load cases go on to step 3.
If you want to determine the SCF for a combined load go on to step 2.

2. Choose the nominal stresses S_b, T_t and S_z
Determine the nominal stress according to the equations given in OVERVIEW: EQUATIONS.
Because only the ratio of the nominal stresses is relevant for SCF calculation every unit is allowed.
Only make sure that all nominal stresses have the same unit and linear elastic material behaviour is still fulfilled.

3. Press button "Calculate SCFs"

The SCF describes the ratio between notch stress and nominal stress.

The nominal stress is determined in the following way:

Bending:	Nominal stress Sb = Mb·Wb-1 with Wb = π⁄32 d3
Torsion:	Nominal stress Tt = Mt·Wt-1 with Wt = π⁄16 d3
Tension:	Nominal stress Sz = Fz·A-1 with A = π⁄4 d2

Following Equations were used for the SCF Calculation .


The ratio r·d^-1 depends on the required ratios r·t^-1 and d·D^-1 and is determined in the following way:

Ratio

r·d-1 = 1⁄2· r·t-1 ( 1⁄ d·D-1 -1)

For all calculations linear elastic material behaviour is assumed.
The Equations are valid for single and combined loading.

Reference:
C. M. Mayr, K. Rother (2019): Improved stress concentration factors for circular shafts for uniaxial and combined loading.
Materials Testing 3 2019 193-203; https://doi.org/10.3139/120.111305