FEA Simulation

[Ellworx]

I've conducted an FEA simulation of a frame designed to connect to the rear of a bulldozer by 4 x 30mm diameter pins as shown in the image below. I have found the software very good, but am having trouble with the contact function and how it applies to the pins.

There is a 0.5mm clearance on diameter between the pins and the clevice and tongue holes. I think there should be three contact surfaces between each pin and surfaces on the clevice and tongues, but I am having trouble selecting these and knowing which contact type to use. At present I can't seem to get any loading on the pins at all.  I have constrained the two tongues on both the vertical and horizontal sufaces.

It would be really good if someone could give me a demonstration of how to do this say for a simple rod end, pin, and clevice under tension?

Thanks in advance

[TMC.Engineering]

Well I gave it a try and the results look ok.

Full disclosure this is not my area of expertise, I don't model connections.  someone else may be able to improve this model.  You should be able download the model from the link.  

I slit the pin hole surface on the plate in half then used a bonded contact on bottom half (3rd pic)

I use sliding no seperation on the pin to clevis

An animation of the model

http://a360.co/1Xk7F92

The Model

http://a360.co/1W5AiJR

Hope it helps

screen shots

[Ellworx]

Thanks Timm

I appreciate the effort you have gone to in assisting. I'm trying to download your model to Fusion to understand better your method, but it is taking for ever or not working at all.

I have had a quick look at what you have done in A360 and think it gets me partly there. What contact have you used for the clevis? and is it on the full surface? I am also having a problem in the FEA where the manual contacts I set up are not visible. They were initially but after deleting one, all subsequent contacts were not visible.

I'm also trying to understand how fusion deals with two surfaces that come in to contact under load. Currently I have surfaces intersecting each other rather then loading each other. This FEA modelling is a bit new to me also even though I have been a mech Engineer for decades now.

Cheers

[TMC.Engineering · Accepted solution]

If you PM me your email I can add you to the project maybe that will be easier to get at the model.

For the contact stratagy I just started with bonded and then started to see what happend whe I changed one at a time. mabey make a simple model to get a handle on how the contact type changes behavior

Here is a screen shot of the contacts. and the bonded pin to clevis the rest can be seen from above message

[Ellworx]

Thanks Timm

Using your advice, lots of trial and error I'm getting close to results I'm happy with.  There is still something odd with the stresses I'm seeing on the pins which I expected to be high, but not to the extreme I'm seeing. It appears to be an issue with the meshing now.

Not sure why it took me so long, but I discovered the view had to be "normal" to obtain a good visual on the contacts. I take it you are in the US? - I'm in Perth Australia which might explain our 12hr out of sync messages!

Ellworx

[TMC.Engineering]

Glad it helped Ellworx,

You are right, I am in the US.

I googled around a little last night and I think the real issue is the need for a different contact type.  If you look at this tutorial made for Autodesk Simulation Mechanical you will see that there is a surface contact type which is what is really needed.  Could be a good feature request to put in for.  

For FEA within F360 I generally ignore stresses around holes as un-reliable.   If pin stress is really needed it might be better to return to something like Shigley's Mechanical Engineering Design book.

Timm