Design and Development of a Lead-Freepiezoelectric Energy Harvester for Wideband, Low Frequency, and Low Amplitude Vibrations

In recent years, energy harvesting from ambient vibrations using piezoelectric materials has become the center of attention due to the fact that it has the potential to replace batteries, providing an easy way to power wireless and low power sensors and electronic devices. Piezoelectric material has been extensively used in energy harvesting technologies. However, the most commercially available and widely used piezoelectric materials are lead-based, Pb [ZrxTi1−x] O3 (PZT), which contains more than 60 weight percent lead (Pb). Due to its extremely hazardous effects on lead elements, there is a strong need to substitute PZT with new lead-free materials that have comparable properties to those of PZT. Lead-free lithium niobate (LiNbO3) piezoelectric material can be considered as a substitute for lead-based piezoelectric materials for vibrational energy scavenging applications. LiNbO3 crystal has a lower dielectric constant comparison to the conventional piezoceramics (for instance, PZT); however, at the same time, LiNbO3 (LN) single crystal presents a figure of merits similar to that of PZT, which makes it the most suitable choice for a vibrational energy harvester based on lead-free materials. The implementation was carried out using a global optimization approach including a thick single-crystal film on a metal substrate with optimized clamped capacitance for better impedance matching conditions. A lot of research shows that standard designs such as linear piezoelectric energy harvesters are not a prominent solution as they can only operate in a narrow bandwidth because of their single high resonant peak in their frequency spectrum. In this paper, we propose, and experimentally validate, a novel lead-free piezoelectric energy harvester to harness electrical energy from wideband, low-frequency, and low-amplitude ambient vibration. To reach this target, the harvester is designed to combine multi-frequency and nonlinear techniques. The proposed energy harvesting system consists of six piezoelectric cantilevers of different sizes and different resonant frequencies. Each is based on lead-free lithium niobate piezoelectric material coupled with a shape memory alloy (nitinol) substrate. The design is in the form of a circular ring to which the cantilevers are embedded to create nonlinear behavior when excited with ambient vibrations. The finite element simulation and the experimental results confirm that the proposed lead-free harvester design is efficient at low frequencies, particularly different frequencies below 250 Hz.

Experimental Investigation of Influences of Traffic Load on the Church of the Assumption of the Virgin Mary in Stará Boleslav

Long-term dynamic loads represent a serious factor which compromise the safety and durability of historical buildings. Though the daily traffic may cause only low level vibrations, which an undamaged structure could safely resist, extreme values of traffic loads over longer periods can be critical having as a consequence the initiation of cracks or the growth of existing ones, such that they may endanger the structure. Good maintenance including control measurements or monitoring can aid in early damage detection and timely planning of remedial actions. The preceding statements are supported by an investigation of the effects of ambient vibrations mainly due to traffic loads on the Basilica of the Assumption of the Virgin Mary in Stará Boleslav. Attention is aimed at a structural fault, its rehabilitation and prognosis for the future.

A High-Precision Low-Cost Analog Acceleration and Vibration Amplifier using PVDF Piezoelectric Sensors

This paper describes a high-resolution analog acceleration and vibration amplifier for use with piezoelectric polyvinylidene fluoride (PVDF) sensors. The purpose of this system is to monitor automated parts placement on integrated circuit boards. One of the problems facing production and inspection equipment is the occurrence of resonant and ambient vibrations. Even small errors can cause systems with micrometer and nanometer precision to exceed design tolerances. This work describes a method to monitor mechanical vibrations through a portable and inexpensive signal-processing unit. The system provides user-selectable gain and filtering modules that are compact and reliable. PVDF is currently used in sensing applications, and its material properties have proven very useful for sensing mechanical stress, strain, pressure, and temperature.

Deposition of Energy using Piezoelectric Material and its Application in TPMS

The limited lifespan in portable, remote and implantable devices and the need to recharge or replace batteries periodically has been a consistent issue. Ambient energy can usually be found in the form of thermal energy, vibrational energy and solar energy. Among these energy sources, vibrational energy presents a constant presence in nature and artificial structures. Energy harvesting through piezoelectric materials by extracting power from ambient vibrations is a promising technology. The material is capable to harvest sufficient energy required to make autonomous and self-powered electronic systems. The characteristic of piezoelectric material is electromechanical coupling between electrical and mechanical domains. The design of a piezoelectric device for the purpose of storing the kinetic energy of random vibrations at the wheel of a vehicle is presented. The harvester is optimized to power the Tire Pressure Monitoring System (TPMS). The aim is to make of the value of power and voltage outputs for different input frequency conditions. A typical TPMS system consists of a battery operated one, in this paper bimorph is designed to powering a TPMS commercial feasibility of this option is compared to existing TPMS modules, which require batteries for operation.

Design and Implementation of a Wireless Sensor Network for Seismic Monitoring of Buildings

This article presents a new wireless seismic sensor network system, especially design for building monitoring. The designed prototype allows remote control, and remote and real-time monitoring of the recorded signals by any internet browser. The system is formed by several Nodes (based on the CC3200 microcontroller of Texas Instruments), which are in charge of digitizing the ambient vibrations registered by three-component seismic sensors and transmitting them to a central server. This server records all the received signals, but also allows their real-time visualization in several remote client browsers thanks to the JavaScript’s Node.js technology. The data transmission uses not only Wi-Fi technology, but also the existing network resources that nowadays can be found usually in any official or residential building (lowering deployment costs). A data synchronization scheme was also implemented to correct the time differences between the Nodes, but also the long-term drifts found in the internal clock of the microcontrollers (improving the quality of records). The completed system is a low-cost, open-hardware and open-software design. The prototype was tested in a real building, recording ambient vibrations in several floors and observing the differences due to the building structure.

Preliminary study on the threshold stiffness and residual displacement of the multangular-pyramid concave friction system (MPCFS) for seismic isolation

In this research, the threshold stiffness and residual displacement of the MPCFS are both investigated. The MPCFS has a higher threshold (breakaway) stiffness and no residual displacement after earthquakes or ambient vibrations, which makes it different from the conventional Curved Surface Slider (CSS). These two features can enable the MPCFS to be more stable when experiencing micro-to-small shakings, and always restore to its central point after earthquakes. With the aim of testifying the two features, a series of analytical simulations are conducted on a four-storey building model equipped with MPCFS. The analytical results are compared with that obtained with CSS. The simulation results validate the aforementioned virtues of MPCFS over the CSS. This indicates that MPCFS has great potential in the engineering practice of seismic isolation.