sm9 16

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PROBLEM (9.16) A thin-walled cylindrical pressure vessel of radius r = 0.4 m and wall thickness
t = 8 mm has a welded spiral seam at an angle of
φ
=60o with the axial direction. The shell is subjected
to an internal pressure of p pascals and an axial tensile load of P = 10π kN applied through rigid end
plates. Calculate the permissible value p if the allowable normal and shear stresses acting simultaneously
in the plane of welding are not to exceed all
σ
= 25 and all
τ
= -10 MPa, respectively.
SOLUTION
o
1509060 =+= θ
2Art
π
=
(400) 50
8
yt
p
p
σσ == =
36
10 10 (400) 1.5625 10 25
2 (0.4 0.008) 2(8)
xp
p
π
σπ
×
=+=×
×+
Equations(8.4):
6
'25 10 (25 50) (25 50)cos300
22 o
xpp
σ =× = + + −
66
1.5625 1.5625
(10 ) (10 ) cos 300
22 o
++
MPap 763.0=
66
'' 1.5625
10 10 (25 50)sin300 (10 )sin300
22
oo
xy p
τ =− × =− − −
MPap 986.0=
Thus, 763
all
p
kPa=
t
p
r
t
σ =
x
y
'
x
'
θ
2
xPpr
At
σ =+
60o
P
P
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