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sm10 39

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PROBLEM (*10.39) A beam AB supported at the ends as shown in Fig. P10.39 carries a
concentrated load P at the mid span C. Determine the vertical deflection of the beam at the end B.
*SOLUTION
For segment AC
EIv1 '' = Px
1
EIv1 ' = Px 2 + C1
2
1 3
EIv1 = Px + C1 x + C2
6
C
A
RA=P
Px
x
L/2
P
B
Px
PL/2
x
L/2
For segment CB
1
EIv2 '' = PL
2
1
EIv1 ' = PLx + C3
2
1
EIv2 = PLx 2 + C3 x + C4
4
Boundary conditions:
v1 (0) = 0 : C2 = 0
v2 (0) = 0 : C3 = 0
Then
L
L
P L 3
L
P
L
v1 ( ) = v2 ( ) :
( ) + C1 ( ) = PL( ) 2 + C4
2
2
6 2
2
4
4
L
L
P L 2
P L
v1 '( ) = v2 '( ) :
( ) + C1 = − L( )
2
2
2 2
2 2
Solving
3
11
C1 = − PL2
C4 = − PL3
8
48
At B(x=0):
11
11 3
vB = v2 (0) = − PL3 =
PL ↓
48
48
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