sm7 10

________________________________________________________________________
PROBLEM (7.10) A rectangular tube is made of an aluminum alloy with an allowable stress
of all
σ
and is acted upon by a bending moment M about the z axis (Fig. P7.10). Calculate:
(a) The bending moment.
(b) The radius of curvature
ρ
of th beam.
Given : all
σ
=120 MPa, E=70 GPa
SOLUTION
33
1(2)(2)
12 12
zbh
I
btht=− − −
33
64
11
(100)(150) (80)(130)
12 12
13.478(10 ) mm
=−
=
(a)
66
,
13.478(10 )120(10 ) 21.565
0.075
all z
all
Mc
I
I
M
kN m
c
σ
σ
−
=
== = ⋅
y
M
z
b
t
t
t
h
t
C
(b) 96
1 21,565 0.02286
(70 10 )(13.478)(10 )
M
EI
ρ
−
== =
×
43.74 m
ρ
=
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