In-situ monitoring of liquid composite molding process using piezoelectric sensor network

The excellent properties of advanced composite materials provide great opportunities for making industrial structures large-scale and intelligent. Liquid composite molding process is suitable for manufacturing complex large-scale composite structures and has the potential for low cost and mass production. In present work, the concept of Networked Elements for Resin Visualization and Evaluation network was developed to measure and monitor the manufacturing process in-situ. This paper investigates the capability of piezoelectric lead-zirconate-titanate sensors in the Networked Elements for Resin Visualization and Evaluation network to monitor two important parameters in liquid composite molding process, including the resin flow front and the progress of the reaction. The piezoelectric lead-zirconate-titanate sensor network can be integrated with a composite structure either installed on the interface between the mold and laminates or embedded inside the laminates during the liquid composite molding process. Experimental results demonstrated that the liquid composite molding process can be effectively monitored by the embedded Networked Elements for Resin Visualization and Evaluation network with a piezoelectric lead-zirconate-titanate sensor network.

Ceramic-Heterostructure-Based Magnetoelectric Voltage Transformer with an Adjustable Transformation Ratio

A voltage transformer employing the magnetoelectric effect in a composite ceramic heterostructure with layers of a magnetostrictive nickel–cobalt ferrite and a piezoelectric lead zirconate–titanate is described. In contrast to electromagnetic and piezoelectric transformers, a unique feature of the presented transformer is the possibility of tuning the voltage transformation ratio K using a dc magnetic field. The dependences of the transformer characteristics on the frequency and the amplitude of the input voltage, the strength of the control magnetic field and the load resistance are investigated. The transformer operates in the voltage range between 0 and 112 V, and the voltage transformation ratio K is tuned between 0 and 14.1 when the control field H changes between 0 and 6.4 kA/m. The power at the transformer output reached 63 mW, and the power conversion efficiency was 34%. The methods for calculation of the frequency response, and the field and load characteristics of the transformer are proposed. The ways to improve performance characteristics of magnetoelectric transformers and their possible application areas are discussed.

Reusable piezoelectric transducer for structural health monitoring using both Lamb wave and electromechanical impedance modes

A variety of structural health monitoring techniques have been developed to support the efficient online monitoring of structural integrity. Moreover, Lamb wave and electromechanical impedance methods are increasingly used for structural health monitoring applications due to their high sensitivity and effectiveness in detecting damage. However, these techniques require transducers to be permanently attached to structures because of the usage of baselines recorded under the condition without damage. In this study, a reusable piezoelectric lead zirconate titanate transducer for monitoring corrosion damage on the aluminum plate is introduced, which can be removed from the test specimen and reused with the repeatability of signals. The reusable piezoelectric lead zirconate titanate transducer is bonded on the aluminum plate using the ethylene-acrylic acid copolymer with an aluminum enclosure. A series of experiments are conducted on an aluminum plate, including the investigation for repeatability of signals and the capability of corrosion detection of the designed piezoelectric lead zirconate titanate transducer through the Lamb wave and electromechanical impedance methods. The simulated corrosion defect with the area of 15 × 15 mm2 is detected during experiments. The experimental results confirm that the reusable piezoelectric lead zirconate titanate transducer can effectively evaluate the corrosion damage to plate structure and can be reused many times.

Microparticle Acoustophoresis in Aluminum-Based Acoustofluidic Devices with PDMS Covers

We present a numerical model for the recently introduced simple and inexpensive micromachined aluminum devices with a polydimethylsiloxane (PDMS) cover for microparticle acoustophoresis. We validate the model experimentally for a basic design, where a microchannel is milled into the surface of an aluminum substrate, sealed with a PDMS cover, and driven at MHz frequencies by a piezoelectric lead-zirconate-titanate (PZT) transducer. Both experimentally and numerically we find that the soft PDMS cover suppresses the Rayleigh streaming rolls in the bulk. However, due to the low transverse speed of sound in PDMS, such devices are prone to exhibit acoustic streaming vortices in the corners with a relatively large velocity. We predict numerically that in devices, where the microchannel is milled all the way through the aluminum substrate and sealed with a PDMS cover on both the top and bottom, the Rayleigh streaming is suppressed in the bulk thus enabling focusing of sub-micrometer-sized particles.

On the importance of pyrolysis for inkjet-printed oxide piezoelectric thin films

Inkjet printing is an attractive low-cost method for the deposition of piezoelectric lead zirconate titanate thin films. Pyrolysis temperature and time are crucial processing parameters to obtain dense layers with state-of-the-art properties.

Эффективное возбуждение магнитоэлектрического эффекта в структуре ферромагнетик-пьезоэлектрик током через магнитный слой

The effective excitation of the magnetoelectric effect in a planar structure amorphous ferromagnet – piezoelectric lead zirconate titanate by alternating current flowing through the magnetic layer was demonstrated. Due to orientation of the exciting magnetic field perpendicular to the constant field and absence of demagnetization, the structure generates even voltage harmonics with efficiency, several times higher than the efficiency of excitation of the effect by volume coils. It was shown that the amplitude of the second harmonic is proportional to the piezomagnetic coefficient of the magnetic layer,increases quadratically with the amplitude of the current and decreases inversely with the biasing magnetic field