Single Piezoelectric Transducer Research Articles

Design of a Compact 3-D Vibration-Assisted Turning Device With Large Amplitude and High Frequency for Diversified Microstructure Sculpturing

The 3D vibration-assisted turning (VAT) has attracted increasing attention for its merits in microstructure sculpturing and ultra-precision machining. However, most current 3D VAT tools adopt complex structures and it is still difficult to implement high frequency and large amplitude simultaneously on a simple integrated tool. Here, a 3D VAT tool with high-frequency and large amplitude adjustment capability is proposed for the first time, which adopts a more stable and compact single sandwich piezoelectric transducer structure. High frequency and large amplitude adjustment capabilities improve the machining efficiency and the range of machinable microstructures. The structure of the tool is simplified by using the sandwich-type single transducer structure, which is convenient to reduce cost and improve machining stability. Surface microstructures with variable inclination angles and distribution ratios are firstly sculptured by the proposed 3D VAT tool, which provides a new idea for surface modification. In addition, surface microstructures with different depths and high-precision microgrooves are machined, and better machining results are obtained. The texture depth and machining efficiency of microstructure are increased with the increase of amplitude and frequency. Microgrooves with a surface roughness of Sa 29 nm, minimized burrs and defects, and a specific cutting force reduction of 54.8% are obtained.

Acoustic driven circulation around cylindrical obstructions in microchannels

We introduce an approach to generate direction-controlled circulation around cylindrical obstructions in channels using a piezoelectric transducer embedded porous-channel device fabricated by photolithography. To transmit acoustic signals into the channel, a single piezoelectric transducer was attached, operating at voltage levels of 5, 10, 15, and 20 V. Microscopic particle image velocimetry was employed to analyze the flow patterns in the channels. The analysis revealed two opposing circulation tendencies around the pillars located at two opposite sides of the channel in the longitudinal direction. The strength of circulation was found to be minimal in the middle of the channel and increased gradually toward the two ends of the channels. Furthermore, we observed that the circulation strength was maximum near the axial centerline and minimum at the boundaries along the width of the channels. Comparing the voltage levels, the higher voltage signals produced a higher strength of circulation than the lower voltage signals in all cases. Additionally, we found that the strength of circulation increased almost linearly and then decayed exponentially in the radial direction from the surfaces of the pillars. The observed velocity fields around individual cylinders matched well with the Görtler vortex model. The reported circulation phenomenon around pillars can be applied in non-contact fluid stirring and mixing in bio-chemical systems and lab-on-a-chip systems and may also provide additional degrees of freedom in object tweezing, trapping, and levitation.

Tuning stability enhancement of all-fiber acousto-optic tunable filter based on multi-piezoelectric transducer

All-fiber acousto-optic tunable filters (AOTFs) have advantages of wide wavelength tuning range, fast tuning speed and low insertion loss. The resonance wavelength of the all-fiber AOTF can be tuned by adjusting the driving frequency of the piezoelectric transducer (PZT). In general, the driving voltage needs to be tuned in wide range in the wavelength tuning process, due to the existence of resonance frequency of the PZT. In this work, we propose and demonstrate a stability-enhanced all-fiber AOTF based on multi-PZT, which can reduce the dependence on the resonant frequency of a single PZT. In the experiment, the acousto-optic coupling efficiency can maintain larger than 80%, when the resonance wavelength of the AOTF is tuned from 1400 nm to 1600 nm, under the condition of a fixed driving voltage. The high tuning stability of the proposed multi-piezoelectric driving configuration can facilitate the practical applications of the all-fiber AOTF, such as the laser wavelength tuning, wavelength-division-multiplexing optical communication, fast optical spectroscopy, and so on.

Performances of Multi-Configuration Piezoelectric Connection with AC-DC Converter in Low Frequency Energy Harvesting System

Harvesting energy by capturing vibration from low frequency energy have been explored extensively. In essence, a single piezoelectric transducer or an array of piezoelectric connections are used to convert kinetic energy into electrical energy in order to produce low frequency energy. In this paper, multi-configuration array piezoelectric connections are used to investigate the performances of different converter circuit types in low energy harvesting applications. This research utilized three pieces of circular piezoelectric sensor to test the combinations of array connection. There are four options for the piezoelectric sensor configuration: parallel (P), series (S), parallel-series (PS), and series-parallel (SP) while the full wave bridge rectifier (FWBR), parallel voltage multiplier (PVM), and parallel Synchronized Switch Harvesting on Inductor (P-SSHI) converter circuit are chosen AC-DC converter circuits. The system is assessed using a variety of load configurations, including 10 kΩ and 1 MΩ with a 3 Hz input frequency. In order to produce the highest possible output of collected power, the observation focuses on identifying the ideal combination of array piezoelectric connections with AC-DC converter. The result shows that 3-Parallel (3P) piezoelectric connection obtained a higher power output among the other types of array piezoelectric which was 5.97μW. The FWBR circuit generated the highest output power with 2.42μW for a combination of piezoelectric sensors array of 3P connection with the AC-DC converter.

An Implantable Wireless System for Remote Hemodynamic Monitoring of Heart Failure Patients.

This article presents an implantable wireless system for remote hemodynamic monitoring, which enables direct, continuous (24/7), and simultaneous measurement of pulmonary arterial pressure (PAP) and cross-sectional area (CSA) of the artery. The implantable device, which measures 3.2 mm × 2 mm × 10 mm, comprises a piezoresistive pressure sensor, an ASIC implemented in 180-nm CMOS, a piezoelectric ultrasound (US) transducer, and a nitinol anchoring loop. An energy-efficient pressure monitoring system, which employs duty-cycling and spinning excitation technique, achieves 0.44 mmHg resolution in a pressure range from -135 mmHg to +135 mmHg and consumes 1.1 nJ conversion energy. The artery diameter monitoring system utilizes the inductive characteristic of the implant's anchoring loop and achieves 0.24 mm resolution within a diameter range of 20 mm to 30 mm, four times higher than echocardiography lateral resolution. The wireless US power and data platform enables simultaneous power and data transfer employing a single piezoelectric transducer in the implant. The system is characterized with an 8.5 cm tissue phantom and achieves a US link efficiency of 1.8%. The uplink data is transmitted by using an ASK modulation scheme parallel to the power transfer and achieves a modulation index of 26%. The implantable system is tested in an in-vitro experimental setup, which emulates the arterial blood flow, and accurately detects fast pressure peaks for systolic and diastolic pressure changes at both 1.28 MHz and 1.6 MHz US powering frequencies, with corresponding uplink data rates of 40 kbps and 50 kbps.

Energy Harvesting and Acceleration Measuring Based on Time-Division Multiplexing Operation of a Single Piezoelectric Transducer

This letter presents a novel approach called energy harvesting and acceleration measuring (EHAM) using a single piezoelectric (PZT) transducer. The EH subsystem is a synchronous electric charge extraction (SECE) interface combining with an energy management circuit, which can harvest energy from PZT. The AM subsystem is for measuring acceleration-related signals. A time-division multiplexing strategy is employed in the EHAM system, where vibration energy is harvested during one period and vibration acceleration is measured in another period, and the harvested energy also powers the AM circuit. The prototyped EHAM system is implemented based on discrete components and tested with a conventional cantilever-based PZT harvester. Experimental results show that the EHAM system can perform EH and AM operations in a time-division multiplexing way. The EH circuit can harvest 1.76 mJ energy during 22 s with a PZT open-circuit voltage of 6 V. The AM circuit can measure accelerations with an accuracy of 95% under the mechanical resonance condition. The EHAM solution can be a candidate for self-powered acceleration measurement.

A novel switch control scheme for concise S–SSHI array interface with multiple piezoelectric energy harvesters

Energy harvesting array formed by multiple piezoelectric transducers (PZTs) can concurrently supply power to the load to improve the reliability. However, the switch control scheme adopted by the existing extensible parallel/series synchronized switch harvesting on inductor interfaces use either dual inductors or redundant peak detectors, both increasing the volume of the circuits. Hence, a novel switch control scheme using RC differential circuit (SCS-RCD) to simplify circuits for multiple piezoelectric harvesters is proposed in this article. It is implemented by reducing the number of switches required for the single piezoelectric block and improving the reuse of components. Extensible S–SSHI (ES-SSHI) circuit based on the SCS-RCD scheme with self-powered performance is proposed. Both theoretical simulation and experimental test demonstrate the effectiveness of the proposed SCS-RCD. The maximum harvested power of prototyped ES-SSHI circuit for single PZT is 3.76 times that of SEH circuit. The results show that the proposed scheme is an alternative option for multiple piezoelectric inputs.

An Enhanced Piezoelectric-Generated Power Technique for Qi Wireless Charging

This paper aims to design and implement a robust wireless charging system that utilizes affordable materials and the principle of piezoelectricity to generate clean energy to allow the user to store the energy for later use. A wireless charging system that utilizes the piezoelectricity generated as a power source and integrated with Qi-standard wireless transmission would substantially affect the environment and the users. The approach consists of a full-wave-rectified piezoelectric generation, battery storage, Qi-standard wireless transmission, and Bluetooth Low Energy (BLE) as the controller and application monitor. Three main functions are involved in the design of the proposed system: power generation, power storage, and power transmission. A client application is conceived to monitor the transmission and receipt of data. The piezoelectric elements generate the AC electricity from the mechanical movements, which converts the electricity to DC using the full-wave bridge rectifiers. The sensor transmits the data to the application via BLE protocols. The user receives continuous updates regarding the storage level, paired devices, and remaining time for a complete charge. A Qi-standard wireless transmitter transfers the stored electricity to charge the respective devices. The output generates pulses to 60 voltage on each compression of a transducer. The design is based on multiple parallel configurations to solve the issue of charging up to the triggering value VH = 5.2 V when tested with a single piezoelectric transducer. AA-type battery cells are charged in parallel in a series configuration. The system is tested for a number of scenarios. In addition, we simulate the design for 11.11 h for approximately 70,000 joules of input. The system can charge from 5% to 100% and draw from 98%. Using four piezos in the designed module results in an average output voltage of 1.16 V. Increasing the number of piezos results in 17.2 W of power. The system is able to wirelessly transmit and store power with a stable power status after less than 0.01 s.

A metasurface radar for steering ultrasonic guided waves

This article presents a new metasurface made of shape memory alloy (SMA) unit cells for steering ultrasonic guided waves in desired emitting directions. The philosophy behind the controllable wave steering performance of the metamaterial system resides in the tunability of its stopband. Such a tunable feature originates from the reversible dramatic variation of the elastic modulus of the shape memory element under the thermal loads. The research starts with the investigation of the adjustable bandgap behavior of the metastructure at different statuses from the scrutiny of the wave dispersive characteristics. Additionally, a systematic parametric study is carried out to unfold the bandgap evolution principle by changing the SMA stub height. Subsequently, numerical modeling of the wave steering behavior is performed by shifting the stopband of one sector within the unit-cell-ring away from the excitation frequency. The wavefield images associated with the wave directionality plots demonstrate that the thermally-activated metasurface area can open up a transmission path for the ultrasonic waves, while the rest portion will not allow guided waves to penetrate. By rotating the designated sector, the metamaterial structure could work like a wave emission radar, realizing the steerable unidirectional wave radiation from a single piezoelectric transducer. In the end, the targeting phenomena are validated by the Scanning Laser Doppler Vibrometry (SLDV) experimental tests. The proposed active metasurface system with the controllable ultrasonic wave interrogating capability may find its application for directional guided wavefield generation in future Structural Health Monitoring (SHM) and Nondestructive Evaluation (NDE) systems.

Effect of hyperthermal cryogenic environments on the performance of piezoelectric transducer

Abstract China’s asteroid exploration mission plans to use multiple ultrasonic drill cross-drilling to anchor the spacecraft on the asteroid surface. To solve the problem of the environmental temperature adaptability of the ultrasonic drill on the surface of asteroids, we propose an ultrasonic drill driven by the Single crystal piezoelectric rings piezoelectric transducer and studied the resonant characteristics of the piezoelectric transducer at hyperthermal and cryogenic environments. First, the ultrasonic drill’s structure and working principle are proposed along with the detailed design of the transducer. Then, the theoretical analysis and finite element method were used to establish the frequency-temperature model of the transducer, respectively. It can be simulated the effect of temperature on the resonant frequency and the nodal plane offset of the transducer. Finally, experiments were conducted to verify the change law of the resonant frequency of the transducer, and tested the drilling performance of the ultrasonic drill in hyperthermal and cryogenic. Our results showed that the transducer’s resonant frequency decreases with the increase of temperature, which is approximately linear; the ultrasonic drill can maintain good drilling performance in the temperature range of −175 to 100 °C. Meanwhile, the drilling pressure is only 5 N, and the drilling power is less than 40 W. This article fills the research gap in the resonant performance of ultrasonic drill in hyperthermal and cryogenic environments, and provides a technical reference for the application of ultrasonic drill in extraterrestrial environments.

Monitoring corrosion-induced thickness loss of stainless steel plates using the electromechanical impedance technique

Stainless steel plates are widely used in steel structures. Corrosion damage of a stainless steel plate can induce the thickness and mass loss of the stainless steel plate. The corrosion-induced thickness loss (CITL) is one of the main reasons for the degradation of the stiffness and bearing capacity of the stainless steel plate, which endangers the safety of the structure and causes economic losses. Therefore, effective monitoring of the CITL of the stainless steel plate can help to ensure the safety of steel structures. In this study, a novel monitoring method for the CITL of the stainless steel plate based on the electromechanical impedance (EMI) technique is presented. The effective mechanical admittance (EMA) of a simply supported thin stainless steel plate under the excitation of a single surface-bonded piezoelectric transducer is derived theoretically; the resonance frequency shift () of the bending vibration mode in the admittance signature is extracted as the CITL-sensitive feature to identify the CITL of the stainless steel plate. The quantitative relationship between and CITL, based on the EMA, is established theoretically for monitoring the CITL of the stainless steel plate. The effectiveness of the proposed method is verified by experiments. The experimental results demonstrate that the proposed method can sensitively identify, accurately quantify and predict the CITL of the stainless steel plate, and has excellent stability and reliability. This method can not only overcome the limitation of the existing statistics-based EMI methods that cannot quantify the CITL, but also compensate for the weakness of commonly-used non-destructive testing methods that cannot quantitatively predict CITL in an on-line monitoring manner. The proposed method provides an effective monitoring and tracking tool for the CITL of the stainless steel plate.

A small three-way valve using particle excitation driven by a single piezoelectric transducer for hydraulic actuator

In this study, a small flow valve for controlling hydraulic actuators was developed. Recently, robot actuators have been used at sites where humans cannot enter, e.g., disaster sites. However, the control system of a multi-degree-of-freedom mechanism requires many control components, consequently increasing the size of the system, which can be a problem. This paper describes the fabrication and evaluation of a small three-way valve particle excitation valve driven by a single piezoelectric transducer. The three-way valve comprises one transducer and two control valves. Because the two valves have different resonant frequencies, the inlet and outlet ports can be switched by applying different driving frequency voltages to the transducer. Further, changing the voltage applied to the transducer regulates the flow rate. The vibration characteristics of a fabricated three-way valve were evaluated. The resonance frequencies at the inlet and outlet ports were 110 kHz and 168 kHz, respectively, and the vibration speed increased with an increase in the applied voltage, indicating that the three-way valve can switch the opening port by changing the driving frequency as well as control the flow rate. Furthermore, we successfully drove an actuator with the fabricated small three-way valve.

Multi-Input SECE Based on Buck Structure for Piezoelectric Energy Harvesting

At present, most piezoelectric energy harvesters (PEHs) are developed based on a single piezoelectric transducer (PZT). But in practical applications, a vibration source can be equipped with PZT array in order to harvest more power. The time-shared multiplexing scheme is mainly employed for multi-input PEHs. There is less study on the synchronized multi-input PEH. In this article, a multi-input synchronous electric charge extraction (MI-SECE) interface based on buck structure for piezoelectric energy harvesting is proposed. Both theoretical analysis and experimental test results demonstrate the effectiveness of the proposed interface. The results show that the MI-SECE interface can extract energy from multi-PZTs simultaneously with any phase difference (0-2π).

Energy output of piezoelectric transducers and pavements under simulated traffic load

Piezoelectric technology introduced to pavement structures can transform the potential renewable mechanical energy in the road into electrical energy, and this provides new ideas for solving the energy supply problem of green and intelligent transportation. The purpose of this study is to quantify the energy output of piezoelectric transducers under vehicle load and thereafter estimate the daily energy output of piezoelectric pavements. The loading process and the energy output model of piezoelectric transducers are analyzed and established, respectively. Through numerical analysis, the energy output variation laws of these transducers are evaluated in three aspects: load, speed, and resistance. The energy output is estimated based on the daily traffic volume statistics. The layout of piezoelectric transducers on the piezoelectric pavement is designed, and the economic benefit of piezoelectric pavements is preliminarily analyzed. Results show that the larger loads and the faster speeds of vehicles, the larger the energy power. One piezoelectric transducer can output 0.058-J energy in a single 0.7-MPa loading. However, higher output power does not guarantee a higher energy output. The maximum energy output occurs at the optimal vehicle speed which is influenced by resistance, but the maximum energy output remains the same at different optimal speeds. By increasing the resistance, the energy output of piezoelectric transducers can reach the maximum at a low speed. Under the daily traffic volume, the energy output of a single piezoelectric transducer can reach 963.99 J, and the daily energy output of a 100-m piezoelectric pavement is approximately equal to the total battery power of 35 mobile phones. Clean energy harvesting in the pavement has broad prospects by using piezoelectric technology, but the energy output of road piezoelectric transducers still needs to be further improved.

A modified piezoelectric ultrasonic composite oscillator technique for simultaneous measurement of elastic moduli and internal frictions at varied temperature.

In this work, a modified piezoelectric ultrasonic composite oscillator technique (M-PUCOT) is developed for measuring a material's elastic moduli and internal frictions, as a function of temperature. Different from the traditional PUCOT that employs two quartz bars as the drive and gauge, here, a single small piezoelectric transducer (PZT) ring is used to drive and sense longitudinal or torsional vibration in a cylinder specimen. Because of the strong piezoelectric effect and relatively large bandwidth of the PZTs compared to their quartz counterpart, the frequency match condition between the transducer and the specimen is not required in this M-PUCOT. For high temperature measurement, a fused quartz spacer, whose resonance frequency matches the specimen's, is bonded between the transducer and the specimen to provide thermal insulation. First, the united equivalent circuit of the transducer- (spacer) -specimen composite system was derived. Then, Young's modulus, longitudinal friction, shear modulus, and torsional friction were explicitly obtained by measuring the resonance frequency and antiresonance frequency of the 2- or 3-component system's electrical susceptance curve using an impedance analyzer. The accuracy of this method was validated both by measuring the system's amplitude-frequency curves using a laser vibrometer and through finite element simulations. The repeatability error of the M-PUCOT is only ∼0.2% for moduli measurement and ∼2.5% for internal friction measurement, which is very promising for studying the moduli and internal friction variations during damage, fatigue, and phase transitions. Finally, the M-PUCOT was employed to measure the variations in moduli and internal frictions of an Fe64Ni36 Invar alloy from room temperature to 500 °C. Results show that above the ferromagnetic phase transition temperature Tc, both moduli reach their maxima, and both internal frictions reach their minima. The proposed M-PUCOT is expected to be widely used in the near future for its quick measurement, high repeatability, and low cost.

Design of a Novel Two-Directional Piezoelectric Energy Harvester With Permanent Magnets and Multistage Force Amplifier.

This article presents the design and testing of a novel two-directional (2-D) piezoelectric stack-based energy harvester for capturing the mechanical energy from the human footstep. The uniqueness of the harvester lies in the fact that the energy of 2-D excitation is scavenged by a single piezoelectric stack transducer, which can reduce the loss of harvestable energy. The harvester is constructed by the integration of permanent magnets, position protection plates, and multistage force amplification frame. The input force and input displacement are restricted to guarantee the device's safety. The reported multistage force amplification frame with leverage mechanism and bridge-type amplifier enlarges the force acting on the piezoelectric stack, which further improves the power output. A linear guiding mechanism based on leaf flexure is applied to minimize the impact of input forces in other than moving directions. Through analytical modeling, the main architectural parameters of the device are determined. Simulation study with finite-element analysis is conducted to optimize the device parameters for achieving the largest force amplification ratio with a high safety factor. A prototype harvester is fabricated for experimental study. Results demonstrate the feasibility of the developed 2-D piezoelectric stack-based energy harvester.

Sonogenetics: Non-invasive cellular manipulation using ultrasound

Optogenetics has been an important tool used in manipulating different cell types, understanding various diseases and has recently been studied as an alternative to electrical manipulation techniques used in a clinical setting. It has the drawback of being an invasive cellular manipulation technique, which limits its applications. Ultrasound is an alternative, non-invasive approach to precisely control cellular function. We propose the development of ultrasound transducers to selectively manipulate cells that have been transfected with mechanically sensitive proteins, in a new technique termed “Sonogenetics.” This study describes recent results in single crystal piezoelectric transducer design and characterization, results from in-vitro studies to identify mechanosensitive proteins, and an in-vivo study where miniature head mounted transducers were used to stimulate the ventral tegmental area of the mouse in order to trigger dopamine release. Ultrasound based stimulation offers superior spatial and temporal control compared to other cellular manipulation techniques. This study enabled development of the tools required for achieving sonogenetic manipulation of cells by presenting novel transducer designs and identification of relevant parameters in order to achieve stimulation of transfected cells.

Measured element phase-shifting interferometry with a single piezoelectric transducer and low-friction workbench

Moving a large-aperture reference mirror (RM) with a significant weight through piezoelectric transducers (PZTs) for phase-shifting introduces considerable challenges and potential problems in conventional reference mirror phase-shifting interferometry (RMPSI). In this report, we present measured element phase-shifting interferometry (MEPSI), which provides an alternative approach for RMPSI without the restrictions of both the aperture and weight of the RM. The proposed MEPSI actuates a low-friction workbench with an ME on board by single PZT to realize high-accuracy phase-shifting, which is not affected by the aperture or the RM weight of. On this basis, a tilt-shift immune phase-shifting algorithm is further applied to restrain the influence of residual tilt-shift errors and other possible error sources on the measuring accuracy. Theoretical analysis and preliminary experiments indicate that the proposed MEPSI can achieve the same level of accuracy as RMPSI and a ZYGO interferometer, and the repeatability of MEPSI, which is not affected by the weight of the ME, is superior to 0.002 λ (PV). MEPSI solves the problems of phase-shifting with large-aperture and heavy-weight RM, thereby providing a simple and feasible alternative approach for conventional RMPSI with the same level of accuracy and with no phase-shift calibration.

Performance Analysis of a Microfluidic Pump Based on Combined Actuation of the Piezoelectric Effect and Liquid Crystal Backflow Effect.

A novel combined actuation method based on the piezoelectric effect and liquid crystal backflow effect is proposed in this paper. The coupling mechanism of a piezoelectric transducer (PZT) and liquid crystal (LC) in a combined driving mode is analyzed, and the governing equations of electromechanical coupling based on inverse piezoelectric effect and the classical Leslie–Ericksen backflow equation are modified under combined driving method. The new multifield coupling dynamic equations for numerical analysis is established. Experimentally, a sandwiched micropump was manufactured and sealed with wet etching technology on a glass wafer. A testing platform was built to analyze the particles motion and the flow rates were measured with both single PZT or LC actuation and combined actuation. Comparing the results of the numerical analysis and experimental testing of the flow rate and LC molecule motion under different driving voltages and frequencies, the performance of the PZT/LC combined driving is found to be superior to that of the single driving mode (PZT or LC driving) under the same driving conditions. Moreover, the new combined driving mode overcome the disadvantages of single driving mode and enhance the driving efficiency significantly. The simulation results are in good agreement with the experimental data. The maximum flow rate of the micropump achieved was 4.494 μL/min with combined driving method.

Design and In Situ Validation of a Guided Wave System for Corrosion Monitoring in Coated Buried Steel Pipes

Ultrasonic guided waves allow long-range screening of the full cross-section of pipelines and are thus ideal for corrosion detection. Systems using removable arrays of sensors for one-off inspections are nowadays widely-available. Guided wave pipeline monitoring, on the other hand, consists of using cheap, robust and usually permanently-mounted sensors to compare the present state of the structure with a previous or undamaged condition. Current application of available monitoring systems shows that robustness and defect detection capability remain a challenge, and some major oil and gas companies therefore consider monitoring to be less well-established. This paper deals with the design and testing of a system designed for monitoring buried and coated pipelines, focusing especially on the development of an array (or collar) of sensors. It starts by showing in detail the characterization of single piezoelectric transducers. Finite element modelling was then used to establish the dimensions of an array of these transducers, and to describe its wave-field generation characteristics. These results were then validated experimentally, initially in laboratory conditions; subsequently, a prototype was built and blind tested in near-operational conditions, which consisted of a buried full-scale pipe segment coated with Stopaq and polyethylene. The pipe segment was subjected to electrolytically accelerated corrosion at uncertain locations and at a rate which was unknown to the authors at LAMEF–UFRGS who were involved in data analysis. Results show that after 2 years of periodic data gathering, the collar showed good stability and robustness, and that it was able to detect corrosion defects found in the dissection of the pipe.