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SOLUTIONS
,TableofContents
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1. Single-Degree-of-Freedom Systems c
2. Random Vibrations c
3. Dynamic Response of SDOF Systems Using Numerical Methods
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4. Systems with Several Degrees of Freedom
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5. Equations of Motion of Continuous Systems
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6. Vibration of Strings and Barsc c c c
7. Beam Vibrations
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8. Continuous Beams and Frames c c c
9. Vibrations of Plates c c
10. Vibration of Shells c c
11. Finite Elements and Time Integration Numerical Techniques
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12. Shock Spectra c
, Chapter 1 c
1.1 Write the equations of motion for the one-degree-of-freedom systems shown in Figures1.72 (a) … (i). Assume
c c c c c c c c c c c c c c c
that the loading is in the form of a force P(t), a given displacement a(t), or a given rotation
c c c c c c c c c c c c c c c c c c c (t) as indicated in the
c c c c c c
c figure.
Figure 1.72 One-degree-of-freedom systems
c c c
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, Solutions
(a) (b)
spring force = (3EI / L )u 3
( )
c c c c c c
spring force = 48EI / L3 u
c c c c c c
3EI
mu + c
u = P(t)
c c
48EI L3
mu + 3 u = P(t)
c c c c
L c
(c) (d)
spring force = 3EI / L3 u − 3EI / L2 (t)
c c c ( c c ) (
c c c c c )
c
spring force = 3EI / L3
c c c ( c c )(u−a)
c c c mu +c
3EI
c
c
u=
c c
3EI
(t)
c
L3 L2
3EI
mu +
L3
c (u − a)= 0
c
c c c c c
3EI 3EI
mu + u= a(t)
c c
c c c c
L3
L3
(e) (f)
spring force = (EA/ L)u
( ) ( )
c c c c c
EA spring force = 2 3EI / L3 u = 6EI / L3 u
c c c c c c c c c c c
mu + u = P(t)
c c
c c c c
6EI
L mu +c
u = P(t)
c c c
L3
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