Evaluation of piezoelectric sensitivity compared to contemporary sensors for structural health monitoring

• Main Author: Andersen, Josh
• Other Authors: Soh Chee Kiong
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Civil engineering::Structures and design
• Online Access: http://hdl.handle.net/10356/71500
• Institution: Nanyang Technological University

Structural health monitoring (SHM) has been studied rigorously during the past few decades as it is becoming an essential tool to improve and monitor structural life. Piezoelectric (PE) sensors and fiber bragg grating (FBG) are some of the most commonly used smart materials. All these smart materials when subjected to DC/AC or light source results in unique health signals/signatures. In this Final Year Project (FYP), sensitivity of the PE sensor was evaluated by understanding such health signatures. Which was compared to a circuit made of 2-3 PE sensors in parallel connections. For this purpose, electromechanical impedance (EMI) based SHM which adopts PE sensors such as lead zirconate titanate (PZT) and piezo diaphragm was adopted. This report presents experimental studies on the sensitivity and robustness of piezo diaphragm when compared to contemporary sensors such as FBG and carbon nano tubes (CNT) for SHM. Experiments were performed by surface bonding a piezo diaphragm on a few 1-D, 2-D and 3-D structures such as strings, aluminium beams, and plates, concrete, as well as the real-life steel frame. Some of the experiments were conducted to study obtained signatures, especially to understand its features such as peaks and valleys. A representative PE circuit was developed, which was connected in parallel to surface bonded piezo diaphragm to boost the sensitivity of the PZT. It was shown through the experiments that boosted signature can detect crack, load, impact and also vibration very well in every structure. Furthermore, peaks of signatures can also be enhanced by the circuit. This will be useful in the future as we can enhance the magnitudes of the peaks on any frequency we want by controlling the circuit.