_______________________________________________________________________
PROBLEM (8.97) A cylindrical tank of inner diameter d and wall thickness t has butt welded
helical seam forming an angle
with the longitudinal axis, as shown in Fig. P8.97. The allowable
normal stress in the weld equals w
. Determine the largest internal pressure p that can be applied in the
tank, using Mohr’s circle.
Given: d = 2r = 1.6 ft, t = 8 mm,
= 55o , w
= 10 ksi
SOLUTION
55
2o
t
ta
pr
t
σσθ
===
2
ta
r
t
σσ
==
τ
13
()
24
avg t a t
σσ σ
=+=
11
()
24
ta
Rt
σσ
=−=
'cos70o
wx avg
R
σσσ
== −
31
cos70
44
tt
σσ
=−
0.664 0.664
t
r
t
σ
==
Introducing the data:
3(1.6 12)
10(10 ) 0.664 0.008
p
=, 6.28
ksi
110o
σavg
σa
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