Learning Forum

[Faraaz-Nadimuddin.Shaikh]

HI all! Im doing a university project and have run into some trouble regarding the procedure to model pre tensioning of a bolted connection. I am simulating only one of the connected parts, the bolt and the other plate are not included in the simulation. I know the material used for the bolt as well as the two connected plates. I also the know pre tensioning torque. My question is how do i model the pretensioning as a boundary condition for the part? 

The original connection looks like this. 

This is the part I'm meant to simulate. 

My ideas: 

1) remote displacements in the hole to restrict horizontal movement. 

2) calculate the force from pre-tensioning and apply it to the hole cylinder.  

I would appreciate any help from the ANSYS gurus lurking here!!! 

[peteroznewman]

If you are simulating the lower part only, simply apply a fixed support to the threaded hole. I would suggest you open the lower part in CAD (or SpaceClaim) and delete the threaded hole geometry and replace it with a simple hole. That will result in a much better mesh. While you are in CAD, you could also imprint on the face that contacts the other part the line where the other part ends at the radiused edge. This is a line that the lower part is bending around. Then you can add a Compression Only support to that face which will be a more accurate simulation of the lower part than simply having a Fixed Support on the threaded hole.  This "reduced" model is appropriate for stresses that are not close to the threaded hole. To get accurate stresses around the threaded hole, you need to include the bolt and the other part.