.Matake method
The Matake criterion can be written in the same way as Findley method:
.
The difference stands in the definition of the critical plane, which is a plane with maximum Ca, i.e. with maximum shear stress range (a mark of any MSSR method) as well. This change allows the criterion to behave correctly according to Papadopoulos [PDG97] under mean torsion loads in contrast to the Findley criterion. The parameters aM and bM are:
The model is tested in [PDG97], [Web99], [Ppg05] with relatively fair results, although it does not reach the best ranking. Later research covered in the FatLim Database shows results of this criterion as one of the worst ones.
Nomenclature:
|
Mark |
Unit |
PragTic variable |
Meaning |
|
|
[MPa] |
shear stress amplitude on an examined plane |
|
|
|
[MPa] |
TENS-1, BEND-1 |
fatigue limit in fully reversed axial loading |
|
|
[MPa] |
maximum normal stress on the plane examined |
|
|
|
[MPa] |
TORS-1 |
fatigue limit in fully reversed torsion |
Methods & Options & Variables of Calculation – Edit
Decomposition
Elasto-plasticity
- No – currently no option implemented
Solution option
- Searched planes <0~BS algorithm, 1~globe analogy, 2~random>
- Number of scanned planes
- Optimize <1~yes, 0~no>
- Only every x-th data-point taken from load history
- Evaluate envelope curve only <1~yes, 0~no>
Solution variable
- Minimum damage – this option is not active for this high-cycle fatigue method
Material parameters
|
E |
[MPa] |
tensile modulus |
|
NU |
[-] |
Poisson’s ratio |
|
TENS-1 |
[MPa] |
fatigue limit in fully reversed push-pull (or plane bending) |
|
TORS-1 |
[MPa] |
fatigue limit in fully reversed torsion |
Result detail variables
Damage fatigue index is computed, not the damage as a reciprocal value to number of cycles or repetitions
FDD1 NCX x-coordinate of the normal line vector of the critical plane
FDD2 NCY y-coordinate of the normal line vector of the critical plane
FDD3 NCZ z-coordinate of the normal line vector of the critical plane
FDD4 ALFA angle between the normal lines to the critical plane and to the free surface
© PragTic, 2007
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