We investigated the efficiency of the storage device based on the piezoelectric generator (PEG) in the form bimorph, which is a circular plate with inertial mass; the active material is a PMN-0,33PT relaxor. The plate is fixed along the contour in the body of the device, which performs vertical harmonic oscillations with a given amplitude and frequency. Our studies based on finite element modeling and numerical calculation in the ANSYS package. A notable feature of relaxors is a significant dependence of their properties on temperature, so in this paper, we studied the relation on operating temperature and the magnitude of the active load of the resonant frequencies, output voltages and electric power of the device with oscillations at these frequencies. Based on performed calculations we have established the values of the active resistances of the external electric circuit for different temperature ranges at which the device is most effective.
Keywords: energy storage, relaxor ferroelectric, PEG
Within the framework of solving the problem of increasing the effectiveness of the directional properties of adaptive systems with parametric sonar emitting antenna in the results of generalization of theoretical and experimental studies of the effect of hydro-irregularities on the characteristic parameter of the antenna. A comparison of the results of calculations of the antenna directivity characteristic parameter derived from the model Khokhlova-Zabolotskaya-Kuznetsova, with the results of experimental measurements of the directional properties of the parametric array. We obtain the normalized dependence of the width of the parametric characteristics of the antenna by lowering the difference frequency from the center frequency of the pump waves of 5 to 16 times. The influence of changes in the speed of sound in the direction of the parametric array. We obtain the normalized dependence of the width of the antenna characteristics of the parametric values of the sound velocity at the surface of the pump transducer. It was found that the greatest impact on the characteristic parameter of the antenna has a change in the speed of sound to a distance equal to the lengths of 1-2 zone diffraction of the pump waves.
Keywords: adaptive sonar system, efficiency, parametric antenna, directivity characteristic
The article discusses the possibility of using LabVIEW to interact with the computer's sound card to create a hardware-software complex of measurement to determine the parameters of the piezoceramic elements . The results of development and experimental research .
Keywords: sound card, LabVIEW, hardware-software complex, piesoceramic element
Research the influence of temperature on some properties piezomaterials DTN system. The mathematical processing of the experimental results conducted. Determined analytical dependences for the purpose of creating a look-up table.
Keywords: piezomaterial, temperature, analytical dependence
The article describes the method of controlling the parameters of the focused ultrasound field by means of the transition layer with desired acoustic characteristics. The article describes the experimental setup and the technological scheme. The description of the program and the formulas used for computer modeling. Presented and evaluated the results of experimental studies and computer modeling: the displacement of the focal point position on the width of the focal spot at the level of 0.707 of the maximum, location and the level of additional peaks. Summarizing the results of experimental setup and computer modeling can be concluded about the possibility of using the transition layer to control the formation of the focal spot.
Keywords: Ultrasound, experimental assembly, layered medium, refraction, computer modelling, transition layer, parameter control, focused ultrasound
In work on the basis of one of the methods of nonlinear acoustics (method of successive approximations) is considered environment as a set of orthogonal plane layers. The analysis is conducted with the division generated total field into components parallel and orthogonal to the direction of its propagation. It is recognized as the primary distribution field distribution along the longitudinal direction with the introduction of the aperture factor and orthogonal to the introduction of the cross-aperture factor. It determines the range of changes of the parameters for biological environments in the case of the nonlinear interaction of acoustic waves in them.
Keywords: nonlinear interaction, quadratic nonlinearity, different layered media, immersion method, transverse aperture factor.
In article ratios for determination of sensitivity of a piezoceramic transducers are received. The effective control method of sensitivity on electric measurements is offered
Keywords: piezoceramic transducers, sensitivity, electric measurements
We consider the construction of the antenna side scan sonar with a bright directional characteristic. This paper presents the results of calculations of the antenna to form a side-scan sonar in a line and its radiation pattern.
Keywords: Rod oscillation mode, piezoelectric, plate, coupling coefficient, opposition, sound pressure directivity characteristic deformation of the plate, the radiating surface
In article questions of nonlinear interaction of acoustic waves in the air environment in the course of distribution are considered. Is shown that the nonlinearity coefficient in the air environment considerably exceeds that in water therefore generation of secondary waves in the air environment is more effective than in water. The main characteristics of interaction pay off. For realization of the parametrical antenna for information transfer the narrow beam offers to use as converters in the rating antenna high-frequency loudspeakers with high sensitivity in the radiation mode. For reduction of level of side petals in the characteristic of an orientation of the antenna of a rating are given the recommendation about an arrangement of converters in the antenna of a rating and to their coordination with Wednesday by means of acoustic loud-hailers. As initial parameters for calculations passport data of loudspeakers get out. Characteristics of the parametrical antenna at its arrangement in air streams are analyzed. Interaction of waves in a stream is described by the non-uniform wave equation in which the member from a convective derivative estimates influence of a stream. Are considered the non-uniform equations for various working out the resultant generated signal the parametrical antenna in the environment with an air stream. Expressions for calculation of additives to the signals generated in a homogeneous environment for distribution of waves of a stream perpendicular and parallel to the direction are removed. It is shown that the air stream in a near zone of the antenna of a rating increases amplitude of the secondary waves generated by nonlinear interaction. Recommendations about use of the parametrical antenna for information transfer in the air environment are made.
Keywords: parametrical antenna, air environment, rating converter, air stream, wave equation
This paper discusses the features of the construction of broadband sonar antennas, intended for environmental monitoring of the aquatic environment, and bottom sediment. The aim of this work is the research and development of broadband antennas sonar systems for environmental monitoring of water environment and the bottom sediment. The goal is achieved by solving two problems: - the application of broadband by its nature, parametric radiating antenna, the principle of which is based on nonlinear interaction of pump waves in the propagation medium; - the application of different frequency transducers to produce the desired band frequency characteristics. The results of studies of broadband antennas illustrate the possibility of constructing broadband signals. The characteristics of broadband parametric sonar antennas, whose operation is based on using the effect of nonlinear interaction of acoustic waves. The results of experimental research of amplitude-frequency characteristics of the broadband parametric antennas. Special attention is paid to the possibility of building broadband hydroacoustic antenna consisting of different frequency converters, mechanical related field. For example, calculations of impedance characteristics of such antennas. Calculated frequency dependence of the active component of the impedance of the antenna and the directivity. In conclusion, the conclusion that the use of different frequency converters allows not only to solve the problem of constructing a broadband antenna systems transmit information to underwater vehicles, but also to provide approximately the same antenna directivity in a wide frequency range. Presents images of the bottom and benthic structures, obtained by using models of parametric profilograph and ultra-wideband sonar.
Keywords: broadband signal; ultra broadband signal; hydroacoustic monitoring; information transfer; parametric hydroacoustic antenna; different frequency converters
According to meteorological studies found natural growth of air temperature, coincident in timing with the beginning of a geomagnetic storm. The data were analyzed according to the temperature of about one hundred meteorological stations. Based on this analysis, it was established phenomenon of short-term (30-60 min) growth of surface layer air temperature during the beginning of the magnetic storm, the detected azimuthal drift of the temperature gradient after the start of geomagnetic storms
Keywords: the low-latitude thermosphere, geomagnetic storm, temperatura air, temperaturny gradient, growth temperature
This article gives an idea of the negative effects of vibration in the aircraft industry in the human body and its internal organs. In the article a lot of attention paid to the analysis of working conditions of pilots and technical workers. The requirements that apply to future product. It reflects the results of testing the properties of vibration protection materials that were used to manufacture the designed product. Reasonable requirements to design personal protective equipment. Submitted sample protection, which was carried out in accordance with all the requirements that were presented to him.
Keywords: Personal protection, protection against vibration, protective vest, evaluation criteria, unfavorable factors of production
The thermal regime of the sea is influenced by the sun’s insolation surface water and heat mass transfer sushi. In the period of the regional warming we can watch heightening of average annual temperature of the surface water up 0,8 °С. The annual variations in sea level in Sukhum district correspond with the annual flow with maximum in summer and minimum in winter. Many years average level of the area of the Sukhum Black Sea is 93 s. For characteristic of hydrological regime of the sea is: the high temperature of the water for a whole year, the predominance of wares which height is two metros and the system is stable and currents. In winter rough sea is predominate 23,9% in the south direction and in summer 30,7%. There are a lot of storms in February and it makes 35,8%.
Keywords: the area of, the temperature the water, wind regime, rough sea, sea level, atmospheric precipitation, hydrological regime, wind effected phenomena, the river flow
Effective application of parametric radiating arrays for detection of objects, buried in bottomsediments, are caused by their possibility to form directed radiation on low frequencies with small initial dimensions. Unlike water, bottom sediments are the environment in which both longitudinal and shift making speeds of acoustic fluctuationsdistribution are presented. Presences of several speed components in bottom sediments give the opportunity toparametric radiating array to generatethe acoustic waves of various types. In given paperthe results of theoretical and experimental researches of the field, created by the parametric radiating array in the multiphase environment «water – bottom sediments» at inclined falling on boundary surface under angles relative to critical are described. It is shown that the longitudinal pump waves, generated in water, and waves of differentialfrequency (DFW) in bottom sediments (BS) are transformed to corresponding shear waves. Besides, because of imaginary passive arrayon boundary surface, the generation of shearedDFWoccurs in BS. Researches were carried out in laboratory hydroacoustic tank. Clay and sand were used asa sample of BS. On the base of time marker the shear DFW in various typeof sediments were allocated. Using obtained theoretical model the basic characteristics of theparametric array in BSwere calculated and experimentally confirmed whileshear DFW excitation.On the results of theoretical and experimental researches, it is proved that transformation, excitation and generation of the shear waves formed by the passive array take placein BS. The results received during research give good coincidence between the theory and practice that illustrate the correctness of the model choice. Besides, experimental results on use of shearDFW in BSfor echo sounder mode are presented. Thus, given method can be used in parametric sonars for BS stratification TO and detection in them of the various alien objects.
Keywords: parametric array, nonlinear interaction, bottom sediments, shear wave of differential frequencies, critical angle
The bulk of the pollutants accumulate in marine sediments. Hence the importance of the problem of the continuous monitoring of the state of the bottom and the bottom of sedimentary structures of inland waters and seas. The paper presents a method of remote sensing bottom soil to determine the speed of sound in the bottom ground. The proposed method allows to carry out measurements at the joint location of the emitter and receiver. The proposed method is a method of beam parameter. For measurements by the method of beam parameter must either have extended the receiving antenna system capable to determine the direction of arrival of the reflected acoustic signals from the bottom with a simple omnidirectional radiator or emit highly directional sound source and relatively easy to take an extended receiving antenna. Using parametric array can be formed acoustic beam width several degrees. This beam width is sufficient to implement the method of beam parameter. The authors have proposed an approximate method of beam parameter allows you to combine the location of the transmitter and the receiver, thus greatly simplifying the receiving antenna. To test the adequacy of the method was carried out modeling and experimental studies. In the simulation, the real parameters laid marine bottom of the layered structure and foster and radiating systems. As a result of the simulation were defined the limits of applicability of the proposed method in the study of marine soils. To determine the velocity of sound in the sea bed sediments with acceptable accuracy must emit acoustic signals at an angle less than 10 degrees. Experimental studies in acoustic basin showed qualitative agreement with the theoretical findings.
Keywords: remote sensing acoustic, classification of marine sediments, parametric profiler
The paper presents the results of theoretical studies of the problem assess the impact of structural features in the design phase in the direction of the acoustic antennas. Consider the generalized algorithm of forming directional characteristics of a special form in the application hydroacoustic problems and solutions of the generalized problem of optimizing the characteristics of antennas and modular design principle. Optimization problem proposed to divide into separate components: optimization of antenna characteristics and optimization of tactical performance speaker system that comprehensively affect the choice of antenna design. The method of constructing an antenna with a pie chart in the horizontal plane when the parametric antenna sector review contains some highly directional converters pumping flat aperture.
Keywords: acoustic antenna, directivity characteristic, sector
Application for monitoring ice conditions devices based on nonlinear acoustics using parametric radiating antenna takes into consideration such characteristics of the formation of the acoustic field, as having both low-frequency difference frequency formed as a result of the nonlinear interaction of two close by the value of the pump waves, and, in fact, high-frequency radiation source pump waves Development of instruments for acoustic monitoring ice conditions require consideration of all possible real oceanographic situations in which they will operate. The article discusses the results of the development of a system for monitoring the panorama of ice conditions in the parametric mode sonar. The analysis of the formation and propagation of the probing signals into acoustic channel parametric meter ice thickness is formulated the principle of measuring the thickness of the reflection (scattering) of the acoustic signals from a locally stratified system with blurred boundaries. Mathematical modeling of the acoustic channel power meter ice thickness and "windows of transparency" on the basis of the calculation of the critical angles of incidence and refraction. The conclusion of the feasibility of using as reference signals of shear waves.
Keywords: ice monitoring acoustic antenna, the critical angle , the transparency window
The paper deals with an influence of a piezoelectric beam geometric dimensions on the primary parameters of piezoelectic constructions. Such parameters as resonance and antiresonance frequencies as well as electromechanical coupling coefficient are investigated. Optimal piezoelectric beam length and width relations are obtained. In conclusion some thoughts on piezoelectric beams practical applications in hydroacoustics are discussed.
Keywords: hydroacoustic antenna, ANSYS, piezoelectric transducer, beam, amplitude frequency characteristic, electromechanical coupling coefficient, modeling, normal mode
In article the hardware-software complex created on the basis of widespread software products is considered. The environment of programming of LabVIEW is used. Results of the pilot studies conducted by means of the developed complex are presented.
Keywords: hardware-software complex, LabVIEW, piezoceramic element, the frequency response of conductivity
This paper considers modeling of piezoelectric generator, which is an element of the devices of energy storage. The piezoelectric generator is a cylindrical coordinate with the attached proof mass. The device frame makes the vertical harmonic vibrations with the given amplitude and frequency. By developed models directly calculated in packages ANSYS and ACELAN, the dependence of the natural frequencies and the output voltage on the geometrical dimensions, material combinations. We numerically studied two cases: vibrations at the resonance frequency and vibrations in the low frequency region at the frequency which is much smaller frequency of the first resonance. In addition, we investigate simplified accounting model of the proof mass.
Keywords:
It is offered to execute approximation by a direct line of values of the active component admittance of piezoresonators in the field of two adjacent points to level 0,5 from the maximum value for reduction error of determination of Q-factor by discrete values of the frequency response. Results of computer simulation and experimental research are provided
Keywords: The piezoresonator, Q-factor, the frequency response of conductivity, measurement in the discrete values
Background. Methods vibrodiagnostics allow to identify the emergence and development of de-fects at an early stage. Of particular relevance is the use of vibrodiagnostic methods for condition monitoring mechanisms under the simultaneous influence many unpredictable factors, varying operating conditions. The vibration causes blurring the boundaries of the focused image, allow-ing you to build a simple compact optical vibration sensor. (Materials and / or methods). Vibro-diagnostics used method for detecting focused optical im-age nodes being monitored. Determination of vibration parameters produced by wavelet analysis of the luminance distribution boundaries of the focused image. (Results). It is shown that the periodic movement of give in the image boundaries bends function (maxima of the second derivative). Character kinks function determined by the change speed of the change of the image boundaries. Continuous wavelet transform of the luminance distribution on the border of the image at a certain level amplitude vibrations cause the appearance of two maxima curves continuous wavelet transform, the amount of which is reduced proportionally. (Conclusion). Theoretical and experimental studies have shown that the optical image registra-tion allows you to register with the sensitivity of the vibration amplitude of 0.1 - 0.15 pixel ma-trix photo detector. For a pixel size of about 5 microns, a linear increase in the order of the opti-cal system 20 sensitivity in amplitude of vibration may reach values of 0.02 microns, which cor-responds to the sensitivity is achieved by holographic interferometry.
Keywords: motor vehicle diagnostics units of vehicles, vibration diagnostics, vibration, continuous wavelet transform (CWT)
This paper considers basic element of device of energy storage which is a piezoelectric generator (PEG) of cylindrical form with the attached inertial mass. A finite element modeling of the device operation is carried out during active load in the external circuit. The main purpose of the operation is to compare the output potential and frequency characteristics of the device known in the literature models of systems with concentrated parameters. On the basis of these models, we can receive the analytical dependence of parameters of PEG with its geometric characteristics and mechanical properties of the used materials. However, the question of the range of applicability of these formulas is still open. In this paper, based on the numerical analysis of finite element models of PEG in package ANSYS, we obtained comparison with the analytical formulas that show the values of some parameters of simplified models and set the boundaries of their applicability.
Keywords: energy storage, PEG, piezoceramics, effective mass, resonant frequency, FEM
The article describes the research of thermodurability of glass-carbon - one of the most promising carbon materials used in the production of luminophors and semiconductor materials, optical single crystals, etc. The aim of this work was to study the behavior glass-carbon in the course of thermo-cyclic testing. As a method of diagnostics of the birth and development of micro-cracks was used by the reception of signals of acoustic emission. It is shown that at heating in the samples glass-carbon there was a strong movement of dislocations in thermocyclic effects ,recognized in the signals of acoustic emission. As the number of pulses when heated above, than during the cooling of the sample, it is evidence of the accumulation of damages in the structure of the cyclic thermal processing glass-carbon samples. It is established, that the curves of the accumulation of defects at the pulses of acoustic emission, differ on the stage of heating and cooling. Proposed to use the curve of the aggregate accounts of acoustic emission pulses as a possible harbinger of destruction when heated glass-carbon of the product.
Keywords: acoustic emission, electrodeposition, the activity of the AE, the remote control.
According to the signal theory vocal speech presents a non-stationary random process due to time variation of its main characteristics. A special emotional impact is gained during ensemble and choir performances. The article provides the correlation analysis results and the autocorrelation function of ensemble singing calculated, taking into account the non-stationary nature of acoustic signals. The studies have shown that there is a certain visual resemblance between correlation portraits of a non-professional student ensemble and a non-professional solo singer. At the same time the correlation portrait of student and professional co-performance tends to a professional singer correlation portrait. This helps to make a quantitative assessment of an ensemble’s professionalism which, alongside with a vocal teacher’s subjective assessment, can provide an objective view on singers’ voices condition to optimize the academic voice training process in an ensemble, which is important when using this voice assessing method in music schools, colleges and universities.
Keywords: Vocal speech, acoustic signal, ensemble singing, choir performance, non-stationary random process, autocorrelation function, quantitative assessment