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sm10 116 119

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PROBLEMS (10.116 through 10.119) A simple beam is loaded as shown in Figs. P10.116
through P10.119. Determine:
(a) The slope at point C.
(b) The deflection at point C.
SOLUTION (10.116)
P
B
2L/3
L/3
RB=P/3
RA=2P/3
M
EI
A1
2 PL
9 EI
A2
x
x1
y
A
tangent at A
x2
θA
C’’
tC/A C’
1 L 2 PL
PL2
A1 =
=
2 3 9 EI 27 EI
1 2 L 2 PL 2 PL2
A2 =
=
2 3 9 EI 27 EI
Thus,
(a) θC / A
x
vC
C
tB/A
2L 1 L 7
+
= L
3 33 9
2 2L 4
x2 =
= L
3 3 9
x1 =
PL3
5 PL3
(7 + 8) =
t B A = A1 x1 + A2 x2 =
243EI
81 EI
2
t
5 PL
θA = − B A = −
81 EI
L
PL2
5 PL2
2 PL2
= A1 ,
θC = θC / A + θ A =
−
=
27 EI 81 EI
81 EI
Continued on next slide
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1L
PL3
)=
= CC ' = A1 (
33
243EI
(b) tC / A
and
1
vC = tC / A − C ' C '' = tC / A − t B / A
3
3
3
PL
5 PL
4 PL3
=
−
=
↓
243EI 243 EI
243 EI
SOLUTION (10.117)
y
M0
A
3EI
L/2
M0/L
EI
x
L/2
C
B
M0/L
M
M0
M0 / 2
x
M/EI
x1
M0/3EI
M0/6EI
A1
A2 A3
x
x3
y
A
x2
θA
C’’
C vC
C’
tangent at A
1 M0 L M0L
=
2 3EI 2 12 EI
1 M0 L M0L
A2 =
=
2 6 EI 2 24 EI
1 M0 L M0L
A3 =
=
2 3EI 2 12 EI
A1 =
B
tC/A
tB/A
L 2 L 5L
+
=
2 32 6
L L 2L
x2 = + =
2 6
3
2L L
x3 =
=
32 3
x1 =
Continued on next slide
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instructional purposes only to students enrolled in courses for which the textbook has been adopted. Any other
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We have
t B / A = A1 x1 + A2 x2 + A3 x3
=
M 0 L2
1 M 0 L2
(5 + 2 + 2) =
72 EI
8 EI
t
1 M0L
θ A = − BA = −
8 EI
L
M0L M0L 1 MoL
+
=
12 EI 24 EI 8 EI
1 M0L 1 M0L
θC = θC / A + θC =
−
=0
8 EI
8 EI
(a) θC / A = A1 + A2 =
2L
1L
) + A2 (
)
32
32
M L2
5 M 0 L2
= 0 (4 + 1) =
144 EI
144 EI
1
5 M 0 L2 1 M 0 L2
1 M 0 L2
vC = tC / A − t B / A =
−
=
↓
2
144 EI
16 EI
36 EI
(b) tC / A = A1 (
SOLUTION (10.118)
w
A
B
a
3wa/4
wa/4
M/EI
x1
wa2/2EI
wa 2
4 EI
A1
A2
-wa2/2EI
y
A
tA/B
a
C
x2
B
Parabolic
spandrel
C’’
C vC
C’
tC/B
θB
B
x
x
tangent at B
Continued on next slide
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1 wa 2
1 wa 3
2a
(2a) =
A1 =
x1 =
2 2 EI
2 EI
3
2
bh
1 wa
a
A2 =
x2 =
=− a
3
3 2 EI
4
t A / B = A1 x1 + A2 x2
7 M 0 L4
wL4
(8 − 1) =
=
24 EI
24 EI
1
7 wa 3
θ B = − tB / A =
2a
48 EI
(a) θC / B
1 wa 2
1 wa 3
(a ) =
=
2 4 EI
8 EI
θC = −θC / B + θ B
=−
(b) tC / B =
1 wa 3 7 wa 3
1 wa 3
+
=
8 EI 48 EI
48 EI
1 wa 3 a
wa 4
( )=
8 EI 3
24 EI
1
wa 4
7 wL4
5 wL4
vC = tC / B − t B / A =
−
=
↓
2
24 EI 48 EI
48 EI
Continued on next slide
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SOLUTION (10.119)
M0
B
A
C L/4
3L/4
M0/L
M/EI
M0/L
x2
M0/4EI
A2
x
A1
-3M0/4EI
x1
tangent at B
tA/B
A
vC
C tC/B
C’
C’’
θB
B
x
9M 0 L
3L 2 L
1 3M 0 3L
A1 = −
=
=−
4 3 2
2 4 EI 4
32 EI
3L 1 L 5 L
1 M0 L M0L
x2 =
A2 =
+
=
=
4 34 6
2 4 EI 4 32 EI
x1 =
t B / A = A1 x1 + A2 x2
M 0 L2
11 M 0 L2
(5 − 27) = −
=
192 EI
96 EI
M
L
t AB
11 0
θB =
=−
96 EI
L
(a) θC / B = A2 =
M0L
32 EI
θC = θ B − A2 = −
11 M 0 L M 0 L
7 M0L
−
=
96 EI
32 EI 48 EI
M L2
1L
)= 0
34
384 EI
M L2
1
11 M 0 L2
1 M 0 L2
vC = tC / B − t A / B = 0 +
=
↑
4
384 EI 384 EI
32 EI
(b) tC / A = A2 (
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