Geology Reference
In-Depth Information
Table 1. Position of compensators following dis-
crete optimization; Good selection by experienced
engineers may yield better results (cf. Figure 6a)
the result of an optimization process too. But if
we think of a structure with 10 floors, we realise
that there are 1024 possible variants of placing
compensators, so some reduction of the number
of proposals is justified. Table 1 and Figure 6a
present the result of such optimizations of the
floor number and positioning. The position of the
compensators is indicated by a C for the different
floors (rows) while the number of compensators
increases vertically. It took more than 500h of
computing time to find these proposals which we
could improve easily by installing the compen-
sators near the maximum amplitudes of the first
Eigen frequencies as Figure 6a demonstrates by
the curve labelled “engineering proposals.” For
example placing three compensators at the floors
numbered 5 (or even 4), 7 and 9 (or 10) shows a
very promising response. This corresponds to the
proposals by the conventional modal contribution
approach as well.
First we decide about the number and position
of compensators. Then we define a range of the
dimensions of the compensators' masses, stiffness.
Here, once more contradictory effects have to be
taken into account. Ranges too small prevent the
evolutionary search from finding interesting re-
gions; ranges too large include the danger that the
Floor
1
2
3
4
5
6
7
8
9
10
1
C
2
C
C
3
C
C C
4
C C
C C
5
C
C
C C C
No. of
Comp.
6
C
C C
C C C
C
7
C
C
C C C
C
C
8
C C
C C C C C
C
9
C
C C C C C C C
C
10
C C C C C C C C C
C
process converges towards infeasible solutions,
as, for example the total weight of the compensa-
tors exceeds the building's mass.
Some tests have to be made here like in all
evolutionary studies. We remember the example
demonstrated in Figure 4c. The fitness function
had been switched from the minimal energy to the
minimal mass at a reasonable energy level. This
is a multi-step approach where different objec-
tives may be helpful. For our 10-storey building
Figure 6. Results of the optimization studies
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