Stress concentration factors for hollow shafts under pure bending

[meetsrivatsan]

Hi everone,
I am trying to make a rough estimate of fatigue life of a hollow shaft under pure bending at a particular load level.The hollow shaft has a shoulder fillet. The minuimum outer diameter is 69mm and the maximum outer diameter is 72mm with a transition radius of 6mm.The thickness of the shaft is 6mm throughout.
To estimate the fatigue life,i need to find the stress concentration (popularly given as stress concentration factor,Kt) due to the transition radius.Though i find the stress concentration factor Kt for solid shafts with shoulder fillet (books like Stress concentration factor by Peterson,Roark's formula for stress and strain) ,i am not able to find the same for hollow shafts under pure bending (though i can find some data for torsion loading).Is Finite element analysis the only option for hollow shafts or is there any published material available?
Any help in this regard will be highly appreciated.

 

[Achy47]

Hello,

Thank you for reaching out with your question. Estimating the fatigue life of a hollow shaft under pure bending can be a challenging task, but there are several approaches you can take to obtain a rough estimate.

One option is to use finite element analysis (FEA) to simulate the behavior of the hollow shaft under the specified loading conditions. This would allow you to obtain the stress concentration factor (Kt) at the transition radius and use it to estimate the fatigue life. However, this approach may require specialized software and expertise in FEA.

Another option is to use published material, such as research papers or technical reports, that have studied the fatigue life of hollow shafts under pure bending. These sources may provide information on the stress concentration factor for a similar geometry and loading conditions to yours. Additionally, some textbooks or handbooks on fatigue analysis may also have data on stress concentration factors for hollow shafts.

It is also worth noting that the stress concentration factor for a hollow shaft with a shoulder fillet may be similar to that of a solid shaft with a shoulder fillet. Therefore, you could potentially use the data for solid shafts as a conservative estimate for your hollow shaft.

I hope this helps guide you in your search for the stress concentration factor for your hollow shaft. If you have any further questions, please don't hesitate to ask. Good luck with your research!