Stress Analysis of clevis pin

[synapse709]

Hello all,

I am totally new to stress analysis and can't find a way to add a torsion stress at the middle of a clevis pin, rotating in a horizontal motion.The test is diagram #4 in the white and yellow image. 

Do I use assemble to place a clevis pin from the content center and if so how do I add the force to the middle of the pin? Is there a way to place the stress points without use of an actual clevis pin being added to the model?

Also, is it ok to ground the bolts after assembling them to ensure a correct test? Should I use the FIX constraint for that instead?

All of inventor is so straighforward and easy to understand, but this seems to be a bit beyond me.

Thanks in advance for the help!

Tim

[synapse709]

OH, I am also having trouble setting a 42 degree angle for the third test. Help with that would also be great!

Here is the model also.

[blair]

I would use the Split-Face tool to create a circular face around each mounting bolt hole and place the ground constraint on the Split-Face. This will properly simulate the contact mounting spot for each bolt/washer head.

You may want to add a pin in the clevis hole and apply your load to this and the FEA within Inventor doesn't ramp the load within a hole to properly match real conditions. Simulation Mechanical 2014 has a "bearing load" which replicates the real life loading of circular holes such as bearing supports.

Looking at your model you shouldn't need the split-face as the bolts pretty much cover the base of the counter-sunk holes.

[blair · Accepted solution]

Create a work plane or work axis for your 42deg and use it as your force vector angle.

[blair]

This video might help you understand the load/force on the "bearing/pin/clevis end"

http://wikihelp.autodesk.com/Simulation_Mechanical/enu/2014/Help/0038-Essentia38/0060-Loads_an60/006...

[synapse709]

Thanks for all the info. They video was helpful and I seem to have figured out how to make the test work, although I am not entirely sure of it accuracy.

"You may want to add a pin in the clevis hole and apply your load to this and the FEA within Inventor doesn't ramp the load within a hole to properly match real conditions. Simulation Mechanical 2014 has a "bearing load" which replicates the real life loading of circular holes such as bearing supports."  - I am not sure what you are saying here exactly. Are you saying I should or should not do it this way. I tried using the pink constraint and adding a pin, however when I try to add the moment force, I find it difficult to get the correct angle (I don't know how to add a place or axis angle as the force angle as mentioned below) and even if I get close and run the test, it has errors saying that parts are not constrained correctly. 

Also you mentioned "make a plane at 42deg and use it as your force vector angle." Where can I set the force vector angle to be that of the plane angle?

Thanks,

TT

[synapse709]

Also, I don't have Autodesk mechanical so trying to accomplish my task as much as possible within the limitations of Inventor 2013 would be the best. I simply want to make sure my model can hold up to the forces.

This model is for a contest from GE on Grabcad.com for a jet engine lifting bracket, and if the forces don't hold up, it won't be considered as a proper entry.

[synapse709]

ah! I found how to add the angle from the plane! THANKS!

[blair]

That was the point of directing you to the Sim-Mech video. It shows the limitation of the FEA within Inventor and the reason I suggested adding the pin and using a assembly rather than the single part model.

[henderh]

Hi Tim and Blair,

  There may be a way to accomplish load case 4 within Inventor Stress Analysis.  We do offer a bearing load in AIP  which only allows compressive forces, in a parabolic load distribution.

  I did a quick mockup, by applying two bearing loads (equal and opposite) to effectively create a moment couple.  As the value of each, I typed in (total moment load / 2*distance_to_center_of_rotation).

  The bottom of the part is fixed, and you can see from the reaction forces that the moment is 5000 lbf-in about the z-axis.  (RMB on the fixed constraint => Reaction Forces).

  Hope this helps...

Best regards, -Hugh

 

[blair]

Thanks,

Ive used it in Sim Mech, didn't realize it was now in Inventor as well.

[henderh]

No worries, we appreciate your replies Blair.  Your contributions are always insightful and helpful.

 I've benefitted and learned quite a bit from your posts over the years