We study the effects of medium rotation on bulk acoustic wave (BAW) propagation. For a theoretical analysis of the BAW propagation characteristics, a motion equation for the plane harmonic waves propagating orthogonal to the rotation axis of the propagation medium was analytically resolved. We found that during medium rotation, the polarization of the waves becomes elliptical with the ratio of the polarization ellipse axes explicitly proportional to the angular velocity of the medium rotation, thereby opening the way for the design of sensitive elements (SE) for perspective angular motion sensors (AMS). Next, an analytical dependence of the SE informative parameter on the Poisson’s ratio of the acoustic duct material was obtained. The rotation effect on the dispersion of BAW propagation velocity was studied. Two approaches to the perspective SE design were proposed. An experimental study of a specially designed test assembly and SE model demonstrated high correlation with theoretical predictions and provided an estimate of a potential SE. Therefore, we believe that the study of acoustic wave propagation under nonclassical conditions is a promising direction for prospective solid-state AMS on based on BAW polarization effects design.

In this paper, the perspectives of using the features of acoustic wave propagation to design rotation rate sensors (RRS) are discussed. The possibility of developing the solid-state sensitive elements (SE) of RRS on acoustic waves of circular polarization is shown. The theoretical basis of bulk acoustic wave propagation under rotation is given. The direct excitation of circularly polarized acoustic wave (CPAW) is considered, the design of the CPAW emitting transducer is offered. The results of experimental studies that indicated the circular nature of the particle motions in the radiated wave are discussed. The principally new concept of the RRS SE design on CPAW, being able to operate under high vibration and acceleration, is proposed. The experimental results revealed a high correlation with theoretical and numerical predictions and confirmed RRS on CPAW operability.

The criteria for the selection of the materials of the plate piezoelectric transducers and the acoustic duct of the sensitive element of the angular velocity sensors are determined. The following materials are considered for piezo plates: quartz (SiO 2 ), lithium niobate (LiNbO 3 ) and lithium tantalate (LiTaO 3 ), as well as langasite (La 3 Ga 5 SiO 14 ). Based on the method proposed earlier by the authors, the optimal cuts for shear wave excitation are found. As the materials of the acoustic duct, quartz, chalcogenide glasses, and several single crystals are considered. As a result, the materials, which provide the optimal design of the sensitive element, are revealed.

Evaluation of the acoustic properties of objects using the results as an informative parameter in determining the physical and mechanical characteristics of a material, is widely used in modern science and technology, as well as in the field of nondestructive testing. In the present paper the possibility of using this approach is considered in relation to the woodworking industry in order to estimate the characteristics of sawn timber modified by the ultrasonic method. The results of previous studies have shown the effectiveness of this technology for increasing the surface density and hardness of wood; therefore, one urgent task is to find criteria that allow evaluating the achieved modification parameters, as well as optimizing the settings of the corresponding technological equipment. In this paper the research results of the acoustic properties of ultrasonic modified aspen wood (Populus tremula) are presented and their applicability as a criterion for estimating the degree of lumber modification is determined.

This paper presents a new type of ultrasonic gyroscopic sensor based on a solid-state standing-wave vibrator, which is promising for shock-resistant applications. A theoretical model of the proposed design, which is a layered structure, and the numerical simulation of its frequency response using the developed software are presented. A test sample of the novel sensing element was made and experimental studies of its frequency response were conducted. The results showed a high correlation between the resonant frequencies both for the real sample research and numerical modeling; thus, the validity of the theoretical model was confirmed. The laboratory investigation of the developed sensing element on a test bench under rotating conditions was carried out and a shift in the standing-wave amplitude proportional to the angular velocity of rotation was revealed; thus, an informative signal for this type of gyroscopic sensor was found. It is shown that the amplitude of the output signal of the new sensor on standing waves compares favorably with the signal levels reported for similar traveling-wave solutions in previous studies. The optimization strategies for the new sensor’s design and operating mode to increase signal to noise ratio are also identified. Thus, the potential of using the developed solid-state standing-wave vibrator as a shock-resistant ultrasonic gyroscopic sensor is supported.

Acoustic properties of aspen wood (Populus tremula),modified by ultrasonic method Акустические свойства древесины осины (Populus tremula), модифицированной ультразвуковым методом