sm9 15

_______________________________________________________________________
PROBLEM (9.15) A cantilever steel shaft of diameter d is subjected to an axial load P and a torque
T as shown in Fig. P9.14. Determine the permissible value of T. The allowable normal and shear stresses
on the spiral weld are all
σ
and all
τ
, respectively.
Given: all
σ
= 20 ksi, all
τ
= 12 ksi, d = 4 in.,
φ
= 50o , P = 40π kips
SOLUTION
o
140905090 =+=+= αθ
3
2
40 10 10
(4)
4
xksi
π
σπ
×
==
x
'
3
16 0.0796
(4)
TTksi
τπ
−
==−
xP
A
σ
=
3
θ
x
16
xy T
d
τ =
y
'
π
Equations(8.4):
'10 10
20 cos280 0.0796 sin280
22 oo
xT
σ ==+ −
.180,0784.08682.05 inkipTT
⋅
=
+
+=
'' 10
12 sin280 0.0796 cos280
2oo
xy T
τ =− =− −
.1225,01382.0924.4 inkipTT
⋅
=
−
=
Thus,
.180 inkipTall ⋅=
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