Development and Application of High Sensitivity Wireless Smart Sensors for Decentralized Stochastic Modal Identification
State of the art smart sensor technology enables deployment of dense arrays of sensors, which is critical for structural health monitoring (SHM) of complicated and large scale civil structures. Despite recent successful implementation of various wireless smart sensor networks (WSSNs) for full scale SHM, the low cost micro electro mechanical systems (MEMS) sensors commonly used in smart sensors cannot readily measure low level ambient vibrations because of their relatively low resolution. Combined use of conventional wired high sensitivity sensors with low cost wireless smart sensors has been shown to provide improved spectral estimates of response that can lead to improved experimental modal analysis. However, such a heterogeneous network of wired and wireless sensors requires central collection of an enormous amount of raw data and off network processing to achieveglobal time synchronization; consequently, many of the advantages of WSSNs for SHM are lost. In this paper, the development of a new high sensitivity accelerometer board (SHM H) for the Imote2 wireless smart sensor (WSS) platform is presented. The use of a small number of these high sensitivity WSSs, composed of the SHM H and Imote2, as reference sensors in the Natural Excitation Technique based decentralized WSSN strategy is explored and is shown to provide a cost effective means of improving modal feature extraction in the decentralized WSSN for SHM. DOI: 10.1061/(ASCE)EM.1943 7889 .0000352. (c) 2012 American Society of Civil Engineers. CE Database subject headings: Structural health monitoring; Probe instruments; Identification; Stochastic models. Author keywords: Structural health monitoring; Wireless smart sensor network; High sensitivity sensor; System identification; Decentralized sensor network.