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PROBLEM (*9.66) Loads P and R are applied at the free end of the post having a diameter d shown
in Fig. P9.66. Calculate the principal stresses and the maximum shearing stress:
(a) At point A.
(b) At point B.
Indicate the results on properly oriented elements.
R = 800π ⋅ N, d = 50 mm
Given: P = 400π ⋅ N,
*SOLUTION
x
T=0.4P
R
C
My=0.4R
d = 50 mm
P = 400π N
R = 800π N
B
A
Mz=0.6P
P
y
z
16T 16(0.4 × 400π )
= 20.48 MPa
=
πd3
π (0.05)3
800π
32(0.6 × 400π )
R M y
σx = + z = −
−
2
A
I
π (0.025)
π (0.05)3
= −1.28 − 61.44 = −62.7 MPa
(a) τ t =
62.7
62.7 2
) + (20.48) 2
± (−
2
2
= −31.35 ± 37.45
σ 1 = 6.1 MPa
σ 2 = −68.8 MPa
τ max = 37.5 MPa
2τ 2(20.48)
=
θ p ' = −16.6o
tan 2θ p ' =
,
σx
−62.7
σ 1,2 = −
x
A
τt
σx
Continued on next slide
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τ (MPa)
68.8 MPa
x
σ2
2θ
'
p
16.6o
y
σ1
C
(−62.7, −20.48 )
σ
(MPa)
A
6.1 MPa
37.5 MPa
(b)
x
σx =
R Myz
+
A
I
B
τ = τt +τ d
VQ 4 V
4P
=
=
(Example 9.4)
Ib 3 A 3π r 2
4 400π
=
= 0.85 MPa
3 π (0.025) 2
and
τ = τ t + τ d = 20.48 + 0.85 = 21.33 MPa
τd =
Similarly,
32(0.4 × 800π )
π (0.05)3
= −1.28 − 81.92 = −83.2 MPa
σ x = −1.28 −
Continued on next slide
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or
instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other
reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States
Copyright Act without the permission of the copyright owner is unlawful.
48.4 MPa
Thus,
83.2
83.2 2
) + (21.33) 2
m (−
2
2
= −41.6 m 46.75
σ 1 = 5.15 MPa
σ 2 = −88.4 MPa
σ 1,2 = −
13.6o
B
5.15 MPa
46.8 MPa
τ max = 46.8 MPa
2τ 2(21.33)
=
,
tan 2θ p ' =
σx
−83.2
θ p ' = −13.6o
Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or
instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other
reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States
Copyright Act without the permission of the copyright owner is unlawful.
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