Sec VIII Div 1 Appendix 14 1

[YBM]

I am designing a rectangular vessel according to App.13(in my case it is actually square). It has a flat integral head with an central round opening greater than 1/2 the shortest span. Reference to UG-39-(c)-(1) requires the head to be designed to App.14.

App.14 does not recognize the non-circular design but refers dimension "A" to be a diameter.

I am inclined to use the "long span" as diameter "A" just as described in UG-34-(b).

Can anyone confirm or deny my logic here?

Thanks!!

 

[brkmech1234]

I can definitely say that your approach would not be conservative. I suggest you use small span and Z factor(defined in UG 34) as correction for rectangular shape.

 

[YBM]

Thanks for your reply.

My shape is square square so in this case the spans are equal. Since the code directs me to use App.14 I don't see how I could use "Z".

 

[brkmech1234]

Design of flat head is not related Appx 14. Refer UG 34 .

Z = 3.4 -2.4 d/D. In your case, it is 1

 

[YBM]

I agree, except that UG-39 (c) and UG-39 (c)(1) direct me to App. 14 because of the large hole in the flat head. What else can I do but use App. 14?

 

[Brandon181]

UG-39(c)(3) When the large opening is any other
type than that described in (c)(1) above, there are no specific
rules given. Consequently, the requirements of U-2(g)
shall be met.

 

[Karloss12]

You may be able to get some of the way with ASME VIII Div 1, however with the complex stresses I expect U-2(g) will be required.

With respect to U-2(g), have a look at Page 31 of the NASA document

http://www.nasa.gov/centers/dryden/pdf/88569main_H-2206.pdf.

It has a fixed sqaure plate with a circular hole with diameter of 60% of square sides.