In this study, a structural health monitoring approach that integrates both electromechanical admittance (EMA) and guided wave (GW) techniques is presented. More specifically, the EMA technique is used for local damage identification, by employing a piezoelectric transducer (PZT) as admittance sensor. Simultaneously, the same admittance sensor is disturbed by selected elastic GWs launched by another PZT to monitor the damages located beyond the sensing area of the admittance sensor. The validation of the integrated approach is achieved by identifying the changes in electrical admittance signatures as measured on the surface electrodes of PZTs. These changes occur when damage alters the mechanical impedance of the examined concrete structure and when propagating GWs encounter structural damage. Finite element models of damages occurring in conventional unreinforced, steel-reinforced or fiber reinforced plastics-reinforced concrete specimens are investigated. Results illustrate that the proposed integrated ...

Damage detection in concrete structures using a simultaneously activated multi-mode PZT active sensing system: numerical modelling

Review of vibration-based electromagnetic–piezoelectric hybrid energy harvesters

Last decade has seen the use of various wired-wireless and contact-contactless sensors in several structural health monitoring (SHM) techniques. Most SHM sensors that are predominantly used for strain measurements may be ineffective for damage detection and vice versa indicating uni-applicability of these sensors. However, there is a rise in piezoelectric (PE) based macro fibre composite (MFC) and lead zirconium titanate (PZT) sensors in SHM, vibration and damping control, etc., due to their superior actuation and sensing abilities. These PE sensors created much interest for their multi-applicability in various technologies such as electromechanical impedance (EMI) based SHM. This research employs piezo diaphragms, a cheaper alternative to several expensive types of PZT/ MFC sensors for EMI technique. These piezo diaphragms have been validated last year for their applicability in damage detection using frequency domain spectrum. Here we further validated their applicability in strain monitoring using real time domain spectrum. Hence, these piezo diaphragms can now be classified as PE sensors and used with the PZT and MFC sensors in EMI technique for monitoring damage and loading. However, no single technique or single type of sensors will be sufficient for large SHM, thus requiring the necessary deployment of more than one technique with different types of sensors such as piezoresistive strain gauge based wireless sensor network for strain measurements to complement the EMI technique. Furthermore, we present a novel procedure of converting a regular PE sensor in the 'frequency domain' to 'real time domain' for strain applications.

https://iopscience.iop.org/article/10.1088/1361-665X/aa5f40/pdf

Load monitoring using a calibrated piezo diaphragm based impedance strain sensor and wireless sensor network in real time

The development of structural health monitoring (SHM) systems and their integration in actual structures has become a necessity as it can provide a robust and low-cost solution for monitoring the structural integrity of and the ability to predict the remaining life of structures. In this review, we aim at focusing on one of the important issues of SHM, the design, and implementation of sensor networks. Location and number of sensors, in any SHM system, are of high importance as they impact the system integration, system performance, and accuracy of assessment, as well as the total cost. Hence we are interested in shedding the light on the sensor networks as an essential component of SHM systems. The review discusses several important parameters including design and optimization of sensor networks, development of academic and commercial solutions, powering of sensors, data communication, data transmission, and analytics. Finally, we presented some successful case studies including the challenges and limitations associated with the sensor networks.

Sensor Networks for Structures Health Monitoring: Placement, Implementations, and Challenges—A Review

Today’s complex modern infrastructure requires robust and autonomous condition assessment as they continue to age with increasing operational loads and extreme climatic events. Structural Health Monitoring (SHM) has recently gained significant interests in inspection and maintenance of large-scale structures. However, large amount of raw data resulting from the data logger of these SHM systems require appropriate tools to systematically visualize and diagnose the data. Building Information Modelling (BIM) is a powerful data management tool that can be utilized as a base platform to analyze and visualize long-term SHM data. Current BIM-based approaches have the capabilities of facilitating design, production, and construction management of structures. BIM models in such approaches can serve as static information sources that contain as-built data. The objective of this paper is to take one-step forward from static towards dynamic BIM by representing and visualizing real-time SHM data. The web-based framework developed in this study features online visualization of data, real-time system identification and efficient decision-making. In this paper, a steel bridge located in London, Ontario is utilized as a case study where both BIM and SHM are integrated in a unified fashion. The proposed framework improves the visualization of SHM data and facilitates infrastructure owners in real-time tracking of critical infrastructure.

/pdf/system-identification-enhanced-visualization-tool-for-4nh95w3emb.pdf

System Identification-Enhanced Visualization Tool for Infrastructure Monitoring and Maintenance

Piezoelectric transducers are widely used for structural health monitoring (SHM) applications. Low weight and small dimensions are only two of the several advantages of piezoelectric transducers. However, these advantages are weakened by using wired connections for supplying the piezoelectric transducers. Besides the additional weight, a long wire connection can have an influence on the measured capacitance. Due to the aforementioned disadvantages, researchers developed different wireless solutions for SHM applications in the last 10 years. In this paper, we present a wireless SHM system, which is designed for SHM applications with piezoelectric transducers and guided ultrasonic waves (GUW). The first part in this paper describes the different parts of the wireless SHM system. One novelty ofthe proposed wireless system is that every wireless signal-processing unit (SPU) in the network can be used for exciting the piezoelectric transducer and also for measuring the voltage signals coming from the piezoelec...

Daniela Riederer

Papers

A wireless sensor system for structural health monitoring with guided ultrasonic waves and piezoelectric transducers