Dear all,

Can any one please explain me, how to calculate the % Elongation as per UCS 79 for double curvature shapes (heads)?

I am doing calculations for one vessel, in which % Elongation for boot head (Elliptical) exceeds 5% & as per code “Heat treatment” is required.

The data for the boot head is as follows,
ID=300 mm, Actual Thk= 6 mm, Nominal Thk= 13 mm,
So, % Elongation as per UCS 79 becomes 18.324% (As per PVElite software).
I am not getting that from where this value comes. I mean how to calculate “Rf” & “Ro” for heads?

My second question is, “Heat Treatment” is required, but which type (i.e. Stress reliving or normalizing etc….).

I am really highly appreciate if anyone can guide me…….

_________________
Makrand Pandurang Sakpal,
Static Equipment Design,
makrands9@gmail.com,
Ph no:- 9967949656.

For 2:1 elliptical head knuckle radius is 0.17D

so

Rf = 0.17D
Ro = infinity (formed from flat plate)

Probably you will get your answer now.

As per code normalizing is not mandatory. Normalizing may be however required if asked in user specification.

Regards

Dear Sir,
Thanks For u r valuable Reply. I got my answer.

_________________
Makrand Pandurang Sakpal,
Static Equipment Design,
makrands9@gmail.com,
Ph no:- 9967949656.

AS PER UCS 79,RF IS FINAL CENTRELINE RADIUS
IN THIS CASE RF WILL BE (300+13+13)/2 =163

SO ELONGATION WILL BE 75X13/163
=5.98%

ALL EXPERTS R REQUESTED TO COMMENT ON THIS METHOD OF CALCULATINF RF

THANKA A LOT
AMOL

Amol,

300 mm is diameter of cylindrical portion. For an ellipsoidal head it becomes major axis and not the diameter.

Refer UG 32 (d) for equivalent radius of 2:1 ellipsoidal head.

DEAR SIR,
THEN FOR TORISPHERICAL DISHEND ALSO ,RF=KNUCKLE RADIUS
ISN'T IT?

THEN IN ABOVE CASE IF DISH IS TORISPHERICAL,
IF KNUCKLE IS 19.56 THAT IS 6% OF CROWN RADIUS(AS PER UG-32(e))
% ELONGATION =75x13/19.56


=49.85%
is it correct?
please guide me.


thanks a lot
amol