Shiv i Report on vessel design

8/17/2019 Shiv i Report on vessel design

1/9

From fg 5.12 the required blank diameter or a 120 inch diameter

elliptical dished head is about 152 inch. The weight o the plate is:

The weight o two heads s !!00 lb.

The "hell weight is:

= 65,500 lb


2/9

The #olume o one head is gi#en b$ eq. 5.1%

V=0.000076 di^2

=0.000076(120)^2

=131 cu ft per head

The total #olume o the two heads is 2&2 cu t. the #olume o the

shell is:

3.14*(10)^2 8 (68)4

= 5340 cu ft.

The total #olume is:262 ! 5340 =5600 cu ft.

The densit$ o 'uid is 5(.! per cu. Ft.

The total weight o 'uid

=(5".7)*(5600)

=334,000 lb

The weight o the #essel and it)s content

=334,000 !65,500!7700

=407,200 lb

Thereore*

+ ,load per saddle-20%*000 lb

/nd

#$=%$

=2.568 = 0.0368


3/9

&a'iu $+itudial bedi+ tre -

The saddle are located close to the heads o the #essel .The

maimum longitudinal bending stress eists at the center o the

span between the saddles and is gi#en b$ :

q 11. :

From fg 11.5:3

2=0.82

Thereore ,

"ince l4r 0.&254&0 0.010%0.005*the compression stress is

not a actor in the design

6$ q 7.15:


4/9

/a+etial hear tre -

/s the head ser#es to sti8en the shell* the tangential shear stress

in the head is gi#en b$ q. 11.2!

From Fig 11.10 and with 9 equal to 120 deg.

5= 0.88

Thereore*

5= (204,000)*(0.88)(60)*(0.625)

= 4780 pi

The tangential shear stress in the shell is gi#en b$ q 11.2 and

as Tshell equals Thead * the shear stress in the head equals the shear

stress in the shell .


5/9

ircuferetial tre at hr f addle-

"ince the shell is sti8ened b$ the head since ; < * q 11.%2

gi#es the circumerential stress at the horn o the middle.

From ig 11.1& /4< 0.5 and 9 120 deg thereore

7 = 0.013

For the condition in which no credit or t is taken or the wear3

plate thickness*

= 4180 10,180

= 14,360 pi

The maimum permissible stress equals :

= 12,650 * 1.25

= 15,800 pi

/s the stress Ft is less than the allowable stress* it is not

necessar$ to take credit or the wear plate.


6/9

Fig 11.27 "ketch o #essel in eample calculation


7/9

%dditial tre i #ead ued a tieer -

The additional stress induced in the head when it is used as a

sti8ener is gi#en b$ q. 11.%%.

From ig 11.1! and with 9 equal to 120 deg

= 0.40

Thereore*

For an elliptical dished head ,= 2.0- the maimum pressure

stress ma$ be taken as equal to the circumerential hoop stress in

the shell . From q. !.5!

6$ eq. !.5&

>sing a one3piece head we fnd that 1.0

= 8650 pi


8/9

The maimum combined stress in the head equals :

2180 !8650 = 10,830 pi

The maimum allowable stress in the head is :

(12,650)*(1.25)

=15,800 pi


9/9

i+ cprei i hell er addle -

The stress in the shell band directl$ o#er the saddle is gi#en b$

q. 11.%&

From ig 11.1! and with 9 equal to 120 deg

= 0.76

=12,700 pi

The allowable stress equals the $ield point di#ided b$

two./ccording to reerence &! the $ield point o "/325* ?rade @

steel equals 70*000 psi.

Thereore

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Shiv i Report on vessel design