High-Performance Piezoelectric Energy Harvesters and Their Applications

A paradigm shift has emerged over the last decade pointing to an exciting research area dealing with the harnessing of elastic structural instabilities for ‘smart’ purposes in a variety of venues. Among the different types of unstable responses, buckling is a phenomenon that has been known for centuries, and yet it is generally avoided through special design modifications. Increasing interest in the design of smart devices and mechanical systems has identified buckling and postbuckling response as a favorable behavior. The objective of this topical review is to showcase the recent advances in buckling-induced smart applications and to explain why buckling responses have certain advantages and are especially suitable for these particular applications. Interesting prototypes in terms of structural forms and material uses associated with these applications are summarized. Finally, this review identifies potential research avenues and emerging trends for using buckling and other elastic instabilities for future innovations.

https://iopscience.iop.org/article/10.1088/0964-1726/24/6/063001/pdf

Buckling-induced smart applications: recent advances and trends

3D displacement measurement model for health monitoring of structures using a motion capture system

System identification in structural engineering

Road surface conditions are continuously degrading due to meteorological conditions, ground movements and traffic that leads to the formation of defects, such as grabbing, holes, and cracks. This article presents a method to automatically distinguish images of road surfaces with defects from road surfaces without defects. This method, based on supervised learning, is generic and may be applied to all type of defects present in the images. They typically present strong textural information with patterns that show fluctuations at small scales and some uniformity at larger scales. The textural information is described by applying a large set of linear and nonlinear filters. To select the most pertinent ones for the current application, a supervised learning based on AdaBoost is performed. The whole process is tested both on a textural recognition task based on the VisTex image database and on road images collected by a dedicated road imaging system. A comparison with a recent crack detection algorithm from Oliveira and Correia demonstrates the proposed method's efficiency.

Automatic Road Defect Detection by Textural Pattern Recognition Based on AdaBoost

: Currently, pavement instrumentation for condition monitoring is done on a localized and short-term basis. Existing technology does not allow for continuous long-term monitoring and network level deployment. Long-term monitoring of mechanical loading for pavement structures could reduce maintenance costs, improve longevity, and enhance safety. In this article, on-going research to develop and validate a smart pavement monitoring system is described. The system mainly consists of a novel self-powered wireless sensor based on the integration of piezoelectric transduction with floating-gate injection capable of detecting, storing, and transmitting strain history for long-term monitoring and a novel passive temperature gauge. A technique for estimating full-field strain distributions using measured data from a limited number of implemented sensors is also described. The ultimate purpose is to incorporate the traffic wander effect in the fatigue prediction algorithms. Preliminary results are shown and limitations are discussed.

Toward an Integrated Smart Sensing System and Data Interpretation Techniques for Pavement Fatigue Monitoring

A double receding contact axisymmetric problem between a functionally graded layer and a homogeneous substrate

Energy harvesting from ambient vibrations in civil structures provides a potential permanent power source for sensor networks used in structural health monitoring. These structures exhibit a narrow, natural frequency-response range, which is generally one to two orders of magnitude lower than the operating frequency spectrum of most piezoelectric-scavenging devices. This considerably limits the levels of harvestable power and thus hinders the implementation of advanced sensing functionalities. In this paper, the improvement of the energy-harvesting characteristics of a bimorph cantilever lead zirconate titanate (PZT) piezoelectric beam is studied. The application of a variable prestress-loading condition is used as a solution to modify the system’s properties. A generalized model that takes into account all the vibration-mode shapes of the beam and the back-coupling effect is derived using the Hamiltonian principle. The model describes the effect of the prestress parameters on the harvestable ener...

Tunable Energy Harvesting from Ambient Vibrations in Civil Structures

This report describes the efforts undertaken to develop a novel self-powered strain sensor for continuous structural health monitoring of pavement systems under the Federal Highway Administration. Efforts focused on designing and testing a sensing system that consists of a novel self-powered wireless sensor capable of detecting damage and loading history for pavement structures. The developed system is based on the integration of a piezoelectric transducer with an array of ultra-low power floating gate computational circuits. A miniaturized sensor was developed and tested. The sensor is capable of continuous battery-less monitoring of strain events integrated over the occurrence duration time. The work conducted under this project resulted in the following: A. The development of a sensor that has the following attributes: (1) Self-powered, continuous, and autonomous sensing; (2) autonomous computation and non-volatile storage of sensing variables; (3) small size such that it can be installed using existing installation procedures that are accepted by State highway agencies and will not constitute a major disruption to current practices; (4) wireless communication to eliminate the need for embedding wires in the pavement structure and the use of fixed data acquisition systems on the side of the road; (5) robustness to withstand harsh loading and environmental conditions during initial construction and throughout the life of the pavement; and (6) the ability of integration in large-scale sensor networks. B. The manufacturing of the sensor electronics and the characterization of their basic functionalities in a laboratory setting. C. The design and characterization of the self-powering scheme based on piezoelectric transduction. D. The design and testing of a robust packaging system to withstand loading and environmental conditions for field implementation. E. The development of a sensor-specific data interpretation algorithm for predicting remaining fatigue life of a pavement structure using cumulative limited compressed strain data stored in the sensor memory.

https://rosap.ntl.bts.gov/view/dot/34779/dot_34779_DS1.pdf

Smart Pavement Monitoring System

Piezoelectric materials have been widely studied as vibration energy harvesters in civil and mechanical systems, given their energy conversion ability and high mechanical to electrical coupling properties. Several external environmental effects, such as temperature, alter the performance of these transducers, thus limiting the longevity and the efficiency of the powered systems. Several techniques are applied to improve the harvesters’ properties and offset the environmental effects. These techniques include the optimization of the piezoelectric material, the use of matching networks to increase the power transfer, and, most importantly, the tuning of the harvester’s resonant frequency to match the fundamental frequency of the input excitation vibration, ensuring a maximum response. In this article, the effects of temperature variations on the energy harvesting characteristics of a bimorph cantilever lead zirconate titanate piezoelectric beam are studied. A proposed mechanical tuning, based on the applica...

Mohamed Rhimi

Papers

Toward an Integrated Smart Sensing System and Data Interpretation Techniques for Pavement Fatigue Monitoring

A double receding contact axisymmetric problem between a functionally graded layer and a homogeneous substrate

Tunable Energy Harvesting from Ambient Vibrations in Civil Structures

Smart Pavement Monitoring System

Passive temperature compensation in piezoelectric vibrators using shape memory alloy–induced axial loading