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Help Understanding Roark Formula: Stress in a Circular Ring

Help Understanding Roark Formula: Stress in a Circular Ring

Help Understanding Roark Formula: Stress in a Circular Ring

(OP)
Following on from my reading of thread507-310434: Help Understanding Roark Formula: Stress in a Circular Ring

I'm trying to find the yield load of a circular ring under tensile loading, given by Roark's 7th Edition, Table 9.2.

Roark's equations show various different loading arrangements, mostly external forces (W) compressing the ring towards the ring center. I'm trying to find the opposite - the ring will be in tension with forces applied outwards from the ring centre. I understand the equations are valid for negative forces i.e. using -W forces for forces acting in the opposite direction.

The problem being analysed is that of a handrail stanchion socket (the circular ring in this case). I am trying to determine the yield stress at the top of the socket given a force applied laterally at the top of the handrail stanchion which is placed in the socket. Please see an example drawing of socket attached for reference. http://www.lk-uk.com/downloads/files/lkfl-std-38.p...

I am new to the world of Roark's formulae and looking for some advice/guidance if this particular loading situation would be applicable.

Having had an initial look through the various loading arrangements in Table 9.2. I think it should be possible but I was hoping someone on his forum may be able to provide me some direction

RE: Help Understanding Roark Formula: Stress in a Circular Ring

Please do not double post, particularly if it's the same forum.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies
[IMG http://tinyurl.com/7ofakss]
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers


Of course I can. I can do anything. I can do absolutely anything. I'm an expert!
There is a homework forum hosted by engineering.com: http://www.engineering.com/AskForum/aff/32.aspx

RE: Help Understanding Roark Formula: Stress in a Circular Ring

In cases like this, there will be some approximation involved in treating the actual ring from the drawing as a circular ring per Roark's. That's a matter of engineering judgment as to how accurate/appropriate things need to be.

You might consider that if the ring completely yields, like a rope, does that mean it's failed? If not, that load case may give unduly conservative results.

Another approximately applicable criteria would be the analysis used for a pin in a hole- see ASME BTH or similar references.

RE: Help Understanding Roark Formula: Stress in a Circular Ring

Have you considered it as a hoop stress problem

TTFN
FAQ731-376: Eng-Tips.com Forum Policies
[IMG http://tinyurl.com/7ofakss]
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers


Of course I can. I can do anything. I can do absolutely anything. I'm an expert!
There is a homework forum hosted by engineering.com: http://www.engineering.com/AskForum/aff/32.aspx

RE: Help Understanding Roark Formula: Stress in a Circular Ring

(OP)
Thanks for the responses.

The sort of answer I am hoping to find is always going to be an approximate solution.

Could you explain further the analysis used for a pin in a hole- see ASME BTH or similar references? - I tried to look this up but was unsuccessful.

Also to answer your question, no, i haven't yet considered it as a hoop stress problem. Could you explain the type of hoop stress analysis in more detail at all?

So far I have been trying to apply various loading cases from Table 9.2 in Roark's

I think that load case 2 with 2 negative point loads acting radially outwards with a small angle of separation (theta) is most applicable solution I can come to...? Although I am skeptical about how simplified this approach may be. I have attached load case 2 from Roark's for your information.

http://files.engineering.com/getfile.aspx?folder=b...

RE: Help Understanding Roark Formula: Stress in a Circular Ring

see: https://en.wikipedia.org/wiki/Cylinder_stress#Hoop... for hoop stress, as well as a multiple of web resources.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies
[IMG http://tinyurl.com/7ofakss]
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers


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There is a homework forum hosted by engineering.com: http://www.engineering.com/AskForum/aff/32.aspx

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