Telechargé par Gingermon

sm10 150 153

publicité
________________________________________________________________________
PROBLEMS (10.150 through 10.153) Determine all of the reactions for the propped cantilever
beam AB shown in Figs. P10.150 through P10.153.
SOLUTION (10.150)
Let M A be redundant.
w
tangent at A
MA
A
B
L
RA
RB
V
wL2/8
wL/2
x
-wL/2
M
2 L wL2 wL2
=
3 8
12
1
1
A2 = − M A ( L) = − M A L
2
2
L/2
wL2/8
A1 =
Parabola
A1
x
A2
-MA
3L/2
2L
L
wL4 M A L2
EIt B / A = 0 = A1 ( ) + A2 ( ) =
−
2
3
24
3
or
1
M A = wL2
8
5
3
Statics: RA = wL ↑
RB = wL ↑
8
8
SOLUTION (10.151)
Assume RA as redundant
tangent at A
MA
A
RA
B
L
RB
M
L/2
M0
-RBL
M0
A1
A2
2L/3
x
A1 = M 0 L
1
1
A2 = − RB L( L) = − RB L2
2
2
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.
L
2L 1
1
EIt B / A = 0 = A1 ( ) + A2 ( ) = RB L − M 0
2
3
3
2
3 M0
or
RB =
↓
2 L
Statics:
3M
∑ Fy = 0 : RA = 2 L0 ↑
1
∑ M A = 0 : M A = 2 M0
SOLUTION (10.152)
Consider RA as redundant.
w0
tangent at B
A
RA
M
MB
B
L
RB
2L/3
RAL
A1
x
A2
4L/3
Cubic
EIt A / B = 0 = A1 (
RA =
or
-w0L2/6
1
1
RA L( L) = RA L2
2
2
2
w L3
1 w0 L
A2 = −
( L) = − 0
4 6
24
A1 =
2L
4L 1
1
) + A2 ( ) = RA − w0 L
3
3
3
30
1
w0 L ↑
10
Statics:
∑F
y
∑M
= 0:
B
= 0:
2
w0 L ↑
5
1
M B = w0 L2
15
RB =
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.
SOLUTION (10.153)
M/EI
Choose RA as redundant.
2L/3
RAL
A1
A
C
A2
L/2
3L/8
Tangent at A
A
B
M2
Parabolic
Spandrel
x
1 L
wL2
M 2 = − w( ) 2 = −
2 2
8
R L2
1 R L
A1 = ( A )( L) = A
2 EI
2 EI
2
1 wL L
wL3
A2 = (−
)( ) = −
3 8EI 2
48EI
B
Requirement:
2L
L 3L
) + A2 ( + )
3
2 8
3
4
R L
7 wL
= A −
3EI 384 EI
t A B = 0 = A1 (
Solving
RA =
7 wL
↑
128
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.
Téléchargement