"Slip layer thickness" is an important factor for the calculation of the "relative notch sensitivity factor" in the ISO standard 6336-3 for bending fatigue. However, the standard didn't make it clear what the "slip layer thickness" term stands for. It only gives its values for different...
It is known that shot-peening increases the fatigue strength of a material as it leads to residual compressive stresses in the surface and subsequently increases the resistance to crack initiation and growth. My question is, does shot-peening affect the resistance to static stresses too? or not...
When deriving S-N curves for gears, is stress calculated from the torque value applied or is it common to use strain gauges?
Also, would the results of testing dog-bone shaped coupons under cyclic loading be representative of the material fatigue model? or do you have to test actual gears to...
Thank you RolMec for your answer. Just to double check I understood you correctly, if I am deriving an S-N curve for a new material/heat-treatment that was not included in the ISO standard and I got a value of the life factor below 0.85 for long life, should I accept it?
Thank you tbuelna and drawoh,
Since fatigue limit is the main deign check for gears, why is it very important to include the yield and tensile strength of the material in gear design software?
Thanks #TVP and #tbuelna for your answers, very helpful.
I am not testing gears myself. But I was recently in touch with a gear-testing lab where they have been deriving an S-N curve for a new material. All their tests (almost a 100 specimens) used the same gear exactly (same geometry...
The ISO 6336-2 standard mentions that the life factor for long life should range between 0.85 and 1; where 1 stands for optimum conditions and 0.85 stands for critical service where pitting lust be minimal. Does anyone know why 0.85 is the minimum value? can you take a lower value like 0.7 or...
The codes of practice for bending and pitting do not mention whether the permissible stress is calculated for the yield strength or the ultimate strength of the material. Do you know any resources that explain this please?
I am not sure what is the outer point of a single pair tooth contact and what is the inner point of a single pair tooth contact (these phrases are mentioned in different sections of ISO 6336-2 and 6336-3). It is very confusing as every tooth contact point would be an outer point to one gear and...
