Geology Reference
In-Depth Information
Figure 4. A schematic of hybrid clipped BEL-PID control algorithm
inhibitory signals act to prevent inappropriate
actions issued by the amygdala (and hence, by
the total model.) This is essentially the gist of the
model described in the article. After the BEL
controller produces appropriate control forces,
the control forces are converted into current/volt-
age signals using a semiactive converter (i.e.,
clipped algorithm). Finally, the converted electri-
cal signal is used as an input signal of the MR
damper system that absorbs seismic energy of
structural systems.
Figure 6 shows how an MR damper is implemented
into a building model. The associated equation of
motion is given by
(
)
−
Mx Cx Kx
+
+
=
“
f
t x x v
,
,
,
M
›
(12)
w
g
,
MR
1
1
1
where
M
,
C
, and
K
are the mass, the damping,
and the stiffness matrices, respectively;
f
MR
is the
MR damping force;
w
g
denotes the ground ac-
celeration; the vector
x
is the displacement relative
to the ground,
x
is the velocity,
x
is the accel-
eration,
x
1
and
x
1
are the displacement and the
velocity at the 1
st
floor level relative to the ground,
respectively,
v
1
is the voltage level to be applied,
and
“
and
›
are location vectors of control
forces and disturbance signal, respectively. The
second order differential equation can be con-
verted into state space
Case Study
Numerical Model
Building-MR Damper Model
To demonstrate the effectiveness of the proposed
approach, a magnetorheological (MR) damper
equipped three-story building structure is inves-
tigated. A typical example of a building structure
employing an MR damper is depicted in Figure 5.
(
)
−
*
*
*
z A z B f
=
+
t z z v
t z z v
,
,
,
E w
MR
1
4
1
g
(13)
(
)
+
y C z D f
*
*
,
,
,
n
,
=
+
MR
1
4
1
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