Structural Health Monitoring Using Smart Sensors - ideals ...

Data processing
Data acquisition
Figure 2.2. Centralized data acquisition approach.
Data acquisition & processing Processing
Figure 2.3. Independent data processing approach.
Figure 2.2). Centralized SHM algorithms are then applied to this data. This approach
allows for application of a wealth of traditional SHM algorithms reviewed in 2.3
Structural Health Monitoring. As the number of smart sensors increases, however, the
measurement data to be centrally collected exceeds the network bandwidth, whether
homerun or hopping communication is adopted. The lack of scalability is a serious
deficiency of this approach. One approach toward a scalable solution is to have a tiered
network. Chintalapudi et al. (2006) utilized lower tier nodes and powerful upper tier
nodes. Assuming upper tier nodes have sufficient power, power consumption at lower tier
nodes is moderated. The tiered network approach is applicable only when installation of
powerful nodes and power supply to these nodes are practical.
The second group, on the other hand, assumes that each smart sensor measures and
processes data independently without sharing information among the neighboring nodes
as illustrated in Figure 2.3 (Lynch et al., 2005; Nitta et al., 2005; Sohn et al., 2002).
Because only the data processing outputs are sent back to the base station, the required
communication can be quite small.
Consequently, this approach is scalable to a large number of smart sensors. However,
the independent sensor node approach does not utilize available information from
neighboring nodes; all spatial information is neglected. For example, information
regarding mode shapes cannot be obtained and used in this approach. Information from
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