Problemas De Pulso
Páginas: 3 (684 palabras)
Publicado: 25 de noviembre de 2012
RESPONSE TO IMPULSIVE LOADING
81
be equal in magnitude to the elastic spring force k vmax . Accordingly, it is evident
that the response spectrum plots of Fig. 5-6 can be used to predict themaximum
acceleration response of mass m to an impulsive acceleration as well as the maximum
displacement response to impulsive loads. When used to predict response to base
acceleration, the plotsare generally referred to as shock spectra.
Example E5-1.
As an example of the use of the above described response
(or shock) spectra in evaluating the maximum response of a SDOF structure to
animpulsive load, consider the system shown in Fig. E5-1, which represents a
single-story building subjected to the triangular blast load. For the given weight
and column stiffness of this structure,the natural period of vibration is
T=
2π
= 2π
ω
W
= 2π
kg
600
= 0.079 sec
10, 000 (386)
The ratio of impulse duration to natural period becomes
0.05
t1
=
= 0.63
T
0.079
andfrom Fig. 5-6, the maximum response ratio is Rmax = 1.33. Thus, the
maximum displacement will be
vmax = Rmax
p0
k
= 1.33
1, 000
10, 000
= 0.133 in
[0.338 cm]
and the maximum totalelastic force developed is
fS ,max = k vmax = 10, 000 (1.33) = 1, 330 kips
[603, 300 kg ]
Total weight = 600 kips
p(t)
Total lateral
stiffness:
k = 10,000 kips ⁄ in
Blast load p(t)1,000 kips
t
t1 = 0.05 sec
Elastic resistance
fS = k v
FIGURE E5-1
SDOF building subjected to blast load.
82
DYNAMICS OF STRUCTURES
If the blast-pressure impulse had been onlyone-tenth as long (t1 =
0.005 sec), the maximum response ratio for this impulse duration t1 T =
0.063 would be only Rmax = 0.20. Thus for an impulse of very shortduration, a large part of the applied loadis resisted by the inertia of the structure,
and the stresses produced are much smaller than those produced by loadings of
longer duration.
It should be kept in mind that although the response...
81
be equal in magnitude to the elastic spring force k vmax . Accordingly, it is evident
that the response spectrum plots of Fig. 5-6 can be used to predict themaximum
acceleration response of mass m to an impulsive acceleration as well as the maximum
displacement response to impulsive loads. When used to predict response to base
acceleration, the plotsare generally referred to as shock spectra.
Example E5-1.
As an example of the use of the above described response
(or shock) spectra in evaluating the maximum response of a SDOF structure to
animpulsive load, consider the system shown in Fig. E5-1, which represents a
single-story building subjected to the triangular blast load. For the given weight
and column stiffness of this structure,the natural period of vibration is
T=
2π
= 2π
ω
W
= 2π
kg
600
= 0.079 sec
10, 000 (386)
The ratio of impulse duration to natural period becomes
0.05
t1
=
= 0.63
T
0.079
andfrom Fig. 5-6, the maximum response ratio is Rmax = 1.33. Thus, the
maximum displacement will be
vmax = Rmax
p0
k
= 1.33
1, 000
10, 000
= 0.133 in
[0.338 cm]
and the maximum totalelastic force developed is
fS ,max = k vmax = 10, 000 (1.33) = 1, 330 kips
[603, 300 kg ]
Total weight = 600 kips
p(t)
Total lateral
stiffness:
k = 10,000 kips ⁄ in
Blast load p(t)1,000 kips
t
t1 = 0.05 sec
Elastic resistance
fS = k v
FIGURE E5-1
SDOF building subjected to blast load.
82
DYNAMICS OF STRUCTURES
If the blast-pressure impulse had been onlyone-tenth as long (t1 =
0.005 sec), the maximum response ratio for this impulse duration t1 T =
0.063 would be only Rmax = 0.20. Thus for an impulse of very shortduration, a large part of the applied loadis resisted by the inertia of the structure,
and the stresses produced are much smaller than those produced by loadings of
longer duration.
It should be kept in mind that although the response...
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