## General Mechanical

#### Fatigue Analysis Shaft – Von Misé Stress Help

• Zhaune
Subscriber

Hi there,

I am conducting a research whose objective is to analyze the fatigue that occurs in a reduction axis by the finite element method, and later to compare the analytical results with the computational ones, using the ANSYS tool.

I am still new to the tool and the results obtained (by ANSYS) are not getting close to the analytics, which should happen.

The shaft has 250 mm, will be supported at both ends by rolling bearings and all of its rounding radii are in the order of 4 mm. The diameter analyzed is 40 mm and the study area is just before the diameter transition to 48 mm (C).

• Ashish Khemka
Ansys Employee
nnPlease refer the following link in Ansys Help which decribes the Fatigue Analysis in Ansys:nnnRegards,nAshish Khemkan
• SaiD
Ansys Employee
Hi,nDid you perform a Static Structural analysis and then add a Fatigue Tool in the results? If not, what you are seeing here are the Static Structural results. In the equations that you have used, could you cross-check if the M is correct? You need to consider the reaction forces too, while calculating the M at location C. The analytical solution before the safety factor is what you would get from a Static Structural analysis.nSain
• peteroznewman
Subscriber
A single ball bearing on the end of a shaft has a very low stiffness for small rotations about the Y and Z axes, assuming the rotational axis is the X axis. An appropriate boundary condition to simulate that is a Remote Displacement on the face of the shaft located at the centerplane of the bearing.nUsing a Remote Force with Behavior set to Rigid is adding a stiffness to the shaft that does not exist. I recommend you split the face on the shaft where each force is applied and use a force on that edge and delete the Remote Force.nPlease show how you calculated M = 186 and what reference was used to get Kf = 1.51?n
• Zhaune
Subscriber
Hi,nThe error was in the support, I switched to remote displacement and applied rotation on the X axis as you said, and the results started to converge to the analytically calculated. Thank you very much Peter, you made my day!n