Yadav Saurabh, Gupta Arpan «Lateral Movement of Particles in a Levitating Acoustic Field» Акустический журнал, 70, № 4, с. pp635-640 (2024)

Acoustic levitation is an interesting technique used for levitating small objects/materials using sound waves. In this study, lateral movement of levitating particles is demonstrated experimentally and numerically. The method can simultaneously move multiple particles and the paper demonstrates levitation for three particles. Initially, an ultrasonic tweezer with a resonance frequency of 40 kHz is used to levitate three particles of average weight of 0.15 mg each. The experimental design is based on numerical simulation. Further, the levitated particles are moved in a lateral direction using two ultrasonic tweezers setup by manipulating the phase of one of the tweezers using Arduino Nano. As evident by simulations, the movement takes place due to the interference of waves leading to the movement of pressure node. The lateral movement of particles can be controlled and even reversed by changing the phase difference.

Wang Z.Y., Yan Y., Gao Z., Shi B. «Inclined Crack Quantification of Plate-Like Structures Based on Circular Sensor Array and Lamb Waves» Акустический журнал, 70, № 3, с. pp560-569 (2024)

Cracks are one of the most common damages to thin plates. Therefore, rapid and accurate detection of cracks is of great significance in the nondestructive testing of thin plates. Most existing nondestructive testing technologies focus on crack localization rather than the quantification of the crack length and orientation. Therefore, this paper proposes a damage index, considering the wave attenuation during propagation, to quantify the crack length and orientation. Lamb waves are transmitted and received by a circular sensor array. Based on the abnormal reflection of the A0 mode of Lamb waves, the reflections at cracks are extracted by the Hilbert transform. The influence of the crack length and orientation are studied parametrically, and the relations between the proposed damage index and crack length and angle are given based on regression analysis.

Yang Y., Peng B., Huang F., Zhu J., He Z., He P., Zhang W. «Temperature Characteristics of Rayleigh Wave and Leaky Surface Acoustic Wave Propagating in Langasite and its Application in Temperature Sensor» Акустический журнал, 70, № 3, с. pp487-493 (2024)

A SAW resonator based on langasite (LGS) substrate with (0, 138.5, 116.6°) cut was designed and fabricated. Simulation and experimental results demonstrate that the resonator has two resonance modes, one Rayleigh wave and the other leaky surface acoustic wave (LSAW). The temperature dependent resonance frequencies of both Rayleigh wave and LSAW had been studied. The results show that the turnover temperature of LSAW mode is below absolute zero, namely, the resonance frequency of LSAW changes monotonically in rather wide temperature range, such as from cryogenic to ultrahigh temperatures. Real-time temperature measurement shows that the temperature sensor based on the LSAW mode can effectively monitor the environment temperature, as the thermocouple does. Our work suggests that the LSAW temperature sensor has great application potential in aerospace field for wide temperature range sensing.

Badykov R.R., Yurtaev A.A., Grigorev E.M., Lomachev A.O. «Manufacturing process simulation of a bump foil for a gas foil bearing» Динамика и виброакустика (Journal of Dynamics and Vibroacoustics с 2014 по 2016 № 2), 9, № 3, с. 6-15 (2023)

The paper describes the tools design process for manufacturing the bump foil of a radial gas foil bearing. The paper proposes an alternative technology for manufacturing the bump foil and a solution to the issues related to this technology, accounting for the compensating effects of residual elastic deformations after the manufacturing process. The significance of the finite element method implementation for residual deformations and stresses accounting is emphasized, aiming to minimize the negative impact of residual elastic deformation on the bearing operational parameters.