Earthquake Engineering Research - HKU Libraries - The University ...

584
the simulated structural response. The observed data of all nodes are used for the identification. In this
case, we asuume Gaussian distrubution for the dynamic parameters whose mean is true value and
standard deviation is 0.01. It is because that the aim of this example is to detect damages of structures.
The number of particles is 5000.
Figure 1. The sketch of the non-stationary structural system
The identified time histories of the damping ratio and natural circular frequency at node 1 are shown in
Fig.2. In these algonthm, probability density functions of dynamic parameters are identified as a set of
particles. We therefore expressed the identified results as the time series-histogram of particles. Fig.2
shows that the identified value of the natural circular frequency converge to the true value for both
cases using MCF and Hybnd filter. But that of the damping ratio tend to converge to the true value
only for the case using Hybrid filter.
Time step
Time step
0005
0015
damping ratio
002 0025 0.03
(a) normal MCF
natural circular frequency
Time step
Time step
001
0.015
damping ratio
002
0.025 Q,03-
(b) Hybrid Filter
2 4
natural circular frequency
Figure 2. Comparison of the time histories of the identified dynamic
parameters at node 1 by normal MCF and that by Hybrid Filter