title: Application of Multiplexed FBG and PZT Impedance Sensors for Health Monitoring of Rocks.
abstract: Reliable structural health monitoring (SHM) including nondestructiveevaluation (NDE) is essential for safe operation of infrastructure systems. Effectivemonitoring of the rock components of civil infrastructures such as tunnels and cavernsremains challenging. The feasibility of employing smart optical fibre sensor (OFS) andpiezoelectric impedance sensor made up of lead zirconate titanate (PZT) forcomprehensive health monitoring of rocks, covering load history monitoring/retrieval aswell as damage assessment is presented in this paper. The rock specimens are subjected tocyclic loading and their conditions are continuously monitored using OFS and PZTsensors. OFS based multiplexed fibre Bragg grating (FBG) sensors are surface bonded onthe rock specimens. Their strain sensing performance is compared with the conventionalelectric strain gauges (ESGs). In addition, PZT patches are also bonded on the specimensto study the damage pattern during different loading cycles. Unlike the FBGs or ESGs,PZT patches are used as bi-functional sensors and actuators, enabling them to be efficientdetectors of incipient damages using the principle of electromechanical impedance. Theexperimental study demonstrated superior performance of these smart FBG and PZTimpedance sensors. This work is expected to be useful for SHM based NDE application ofrock structures such as caverns and tunnels.
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798. cywyang@ntu.edu.sg.
authors.forename: Yaowen
authors.initials: Y
authors.lastname: Yang
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798. venu.iisc@pmail.ntu.edu.sg.
authors.forename: Venu Gopal Madhav
authors.initials: VG
authors.lastname: Annamdas
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798. cwang@ntu.edu.sg.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Building and Infrastructure Division, Defense Science & Technology Agency, Singapore 109679. zyinxin@dsta.gov.sg.
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Zhou
keywords: FBG; Optical fibre sensors; PZT; impedance; rock; structural health monitoring