Structural Health Monitoring Using Smart Sensors - ideals ...
Structural Health Monitoring Using Smart Sensors - ideals ...
Structural Health Monitoring Using Smart Sensors - ideals ...
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ABSTRACT<br />
Industrialized nations have a huge investment in the pervasive civil infrastructure on<br />
which our lives rely. To properly manage this infrastructure, its condition or serviceability<br />
should be reliably assessed. For condition or serviceability assessment, <strong>Structural</strong> <strong>Health</strong><br />
<strong>Monitoring</strong> (SHM) has been considered to provide information on the current state of<br />
structures by measuring structural vibration responses and other physical phenomena and<br />
conditions. Civil infrastructure is typically large-scale, exhibiting a wide variety of<br />
complex behavior; estimation of a structure's state is a challenging task. While SHM has<br />
been and still is intensively researched, further efforts are required to provide efficient and<br />
effective management of civil infrastructure.<br />
<strong>Smart</strong> sensors, with their on-board computational and communication capabilities,<br />
offer new opportunities for SHM. Without the need for power or communication cables,<br />
installation cost can be brought down drastically. <strong>Smart</strong> sensors will help to make<br />
monitoring of structures with a dense array of sensors economically practical. Densely<br />
installed smart sensors are expected to be rich information sources for SHM.<br />
Efforts toward realization of SHM systems using smart sensors, however, have not<br />
resulted in full-fledged applications. All efforts to date have encountered difficulties<br />
originating from limited resources on smart sensors (e.g., small memory size, small<br />
communication throughput, limited speed of the CPU, etc.). To realize an SHM system<br />
employing smart sensors, this system needs to be designed considering both the<br />
characteristics of the smart sensor and the structures to be monitored.<br />
This research addresses issues in smart sensor usages in SHM applications and<br />
realizes, for the first time, a scalable and extensible SHM system using smart sensors. The<br />
architecture of the proposed SHM is first presented. The Intel Imote2 equipped with an<br />
accelerometer sensor board is chosen as the smart sensor platform to demonstrate the<br />
efficacy of this architecture. Middleware services such as model-based data aggregation,<br />
reliable communication, and synchronized sensing are developed. SHM Algorithms<br />
identified as promising for the usage on smart sensor systems are extended to improve<br />
practicability and implemented on Imote2s. Careful attention has been paid to integrating<br />
these software components so that the system possesses identified desirable features.<br />
The damage detection capability and autonomous operation of the developed system<br />
are then experimentally verified. The SHM system consisting of ten Imote2s are installed<br />
on a scale-model truss. The SHM system monitors the truss in a distributed manner to<br />
localize simulated damage.<br />
In summary, this report proposes and realizes a scalable and autonomous SHM system<br />
using smart sensors. The system is experimentally verified to be effective for damage<br />
detection. The autonomous nature of the system is also demonstrated. Successful<br />
completion of this research paves the way toward full-fledged SHM systems employing a<br />
dense array of smart sensors. The software developed under this research effort is opensource<br />
and is available at: http://shm.cs.uiuc.edu/.