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Mingjia09
Participant

Join Date: Sep 2009
Posts: 4

Calculating Extreme Fiber Elongation

09/04/2009 11:53 AM

Hi,

How to calculate extreme fiber elongation according to UCS 79. Currently, i am designing a air receiver according to ASME section 8. Just wanted to know how to get the extreme fiber elongation for the cylinder? What will be the value of Rf and Ro if my OD of cylinder is 1500mm, the min thickness is 11.874mm and propose thickness is 13mm.

Regards

Mingjia
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Dilip Kumar Singh
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Join Date: Jan 2009
Location: Navi Mumbai
Posts: 9
Good Answers: 1
#1

Re: Calculating Extreme Fiber Elongation

09/05/2009 12:34 AM

as per UCS79, extreme fibre elongation for a cylinder is 50*t*(1-Rf/Ro)/Rf

As ur OD is 1500mm and proposed thk is 13mm. Then ur t=13mm, Inside Readius=750-13=737mm, Rf= final centeline distance (737+13/2)=743.5. Rt is infinity for a flat plate as at the initial stage cylinder plate will be a flat plate.

So ur extreme fibre elongaton will be 50*13*(1-743.5/infinity)/743.5=0.8742
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Anonymous Poster
#2
In reply to #1

Re: Calculating Extreme Fiber Elongation

09/05/2009 3:52 AM

Really thanks alot
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2
Abdel Halim Galala
Guru
Engineering Fields - Piping Design Engineering - New Member Egypt - Member - Member since 02/18/2007

Join Date: Feb 2007
Location: Cairo, Egypt
Posts: 1733
Good Answers: 248
#3

Re: Calculating Extreme Fiber Elongation

09/05/2009 4:10 AM

Extreme Fiber Elongation Calculations

[UCS-79]

Must be calculated for both cylinder (single curvature) & heads (double curvature).
..........

Shell

OD = Outside Diameter of Vessel....1500MM
.t = Shell Plate Thickness....13MM
.D = Shell Inside Diameter....1474MM
.Rf = Final Centerline Radius = D / 2...737MM
.Ro = Original Centerline Radius.( Rf = infinity for flat plate)∞.
.Rf / Ro........
.% extreme fiber elongation = 50 ( t / Rf )(1 - Rf / Ro)..0.8819539.
........< 5%

OK

..........

Head

OD = Outside Diameter of Vessel...1500MM
.t = Head Plate Thickness....15MM
.D = Inside Diameter of Head Skirt...1470MM
.Rf1 = Knuckle Radius = 0.17 D.

[UG-32(d)]

..249.9MM
.Rf2 = Spherical Radius = 0.90 D.

[UG-32(d)]

..1323MM
..........
.% extreme fiber elongation (knuckle radius) = 75 ( t / Rf 1)(1 - Rf1 / Ro)4.5018007.
........< 5%

OK

.% extreme fiber elongation (spherical radius) = 75 ( t / Rf2 )(1 - Rf2 / Ro)0.8503401
........< 5%

OK

Note. For cylinders, Rf can be calculated, Rf = (D + t) / 2

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Mingjia09
Participant

Join Date: Sep 2009
Posts: 4
#4
In reply to #3

Re: Calculating Extreme Fiber Elongation

09/06/2009 5:58 AM

Dear Sir,

Really thanks for your effort.
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tannguyen
Participant

Join Date: Sep 2010
Posts: 2
#7
In reply to #3

Re: Calculating Extreme Fiber Elongation

09/30/2010 12:25 AM

Dear Sir.

I'm thinking there are some minor of misunderstanding with your Rf1 (final centerline radius of skirt).

In my opinion, Rf1= Knuckle Radius + 0.17t.or Rf1=0.17(D+t)=0.17(1470+15)=252.45mm.

Is it right?

I'm in this trouble from Vietnam company and I having not much exprience about this matter. Please help to clarify it.

Thanks.

Tan
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pilot joe
Associate

Join Date: Nov 2011
Posts: 31
#9
In reply to #3

Re: Calculating Extreme Fiber Elongation

01/10/2016 5:24 PM

Dear Mr. Abdel halim,

As usual , thanks a lot for the informative and detailed answer , unfortunately I've a couple of points here has not been yet clarified :

1- In Table UG-79-1 in the general notes , the code referred to the term " Rf " as the Final " mean " radius. in my understanding for the term " mean " shouldn't the equation in this case for the knuckle radius = 0.17Di + t nominal /2 ? (where Di is the vessel internal diameter , and t nominal is the head selected thickness ). correct me if I am wrong please , as we already considered the same equation for the cylinder as you stated in your comment.

2- If the material we`re working with is ASME SA516 Grade.70(N) which has P-No.& Group-No. of 1 and 2 respectively , can we consider the extreme final elongation of 40% instead of 5% if the 5 conditions stated in paragraph (UCS-79) don't exist ? can you clarify why in your solution you chose 5% not 40%?

Best regards.
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ibadullahmomin
Participant

Join Date: Jan 2019
Posts: 1
#10
In reply to #3

Re: Calculating Extreme Fiber Elongation

01/17/2019 11:20 PM

Dear Sir,

Please tell me how you got the percentage 5% in both the case what is the formula for % calculation

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Anonymous Poster
#5

Re: Calculating Extreme Fiber Elongation

10/01/2009 1:43 AM

How to calculate Extreme Fiber Elongation for Torispherical and Toriconical Heads?

Can I get the equations including for Rf?
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Anonymous Poster
#6
In reply to #5

Re: Calculating Extreme Fiber Elongation

10/12/2009 5:28 AM

thx a lot sir,,, Also can u please give me a note of impact test reqirement as per ASME Sec viii div 1...????...
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tannguyen
Participant

Join Date: Sep 2010
Posts: 2
#8
In reply to #6

Re: Calculating Extreme Fiber Elongation

09/30/2010 12:36 AM

Dear,

Regarding to Impact test. Please look to UCS.66 in ASME code, Sec VIII, Div1.

Best regards,

Tan
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Users who posted comments:

Abdel Halim Galala (1); Anonymous Poster (3); Dilip Kumar Singh (1); ibadullahmomin (1); Mingjia09 (1); pilot joe (1); tannguyen (2)

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