Multiphase mobile sensor network for beam health monitoring
Thomas J. Matarazzo, Matthew Horner, K. Koser, Shamim N. Pakzad · 2016
The text in this paper is for visual purpose only. No rights can be taken from this . In Structural Health Monitoring (SHM), the efficiency of a sensor network is challenged when a large quantity of sensors is required for data collection. Smaller sensor networks are preferable as they have reduced setup, communication, reliability, and power demands. With fixed sensors, the spatial information in the data is restricted by the quantity of sensors, thus there is a tradeoff between network size and obtainable knowledge. In system identification (SID), data with rich spatial information permits accurate modal property estimation ( Pakzad and Fenves 2009 ) and high-resolution mode shapes. Optimal sensor placement techniques have been developed to avoid redundant data collection and determine a proper balance between cost (associated with network size) and achievable knowledge ( Chang and Pakzad 2015 ). Such theoretically optimal locations may be obstructed or inaccessible due to the architectural or structural features ( Bagajewicz and Sa 2000 ). This tradeoff between network size practicality and spatial density is the inherent flaw of fixed sensor networks. In SHM, a few mobile sensors can replace a large quantity of fixed sensors. A mobile sensing platform and test bed were developed to validate this technique at the ATLSS Engineering Center at Lehigh University. Figure 1 (a) Mobile sensor cart equipped with wireless sensor; (b) Simply supported plate specimen and motor-driven pulley assemblage. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig44_1.jpg"/> Figure 2 depicts the two mobile sensing phases considered in this study. In phase I, the two sensor groups travel in opposite directions simultaneously, thus the distance between the groups varies with time. In phase II, the directions of the sensors are synchronized so that the distance between the two sensor groups remains constant. Figure 2 (a) Illustration of mobile sensor phase I where four mobile sensors travel in opposite directions, beginning from the supports; (b) in mobile sensor phase II four mobile sensors move in the same direction, in two clusters. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig44_2.tif"/>