sm7 39

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PROBLEM (7.39) Determine the largest permissible load P that the cantilever spring shown in
Fig. P7.38 can carry for an allowable stress of all
σ
= 20 ksi, fillet radius r = 3/8 in., and width b =
5/8 in.
SOLUTION
At a section through B
12
BP=, 33
1(0.625)(1.5) 175.78 10 .
12 4
I
in
−
==×
M
3
12 (0.75) 51.2
175.78 10
B
nom Mc PP
I
σ
−
== =
×
0.375 2.25
0.25 1.5
1.5 1.5
rD
dd
== ==
, 1.4K
=
(Fig. 7.13)
Thus,
3
1.4(51.2 ) 20 10
all P
σ ==×
b
gives
279
all
Pl=
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