Showing papers in "IEEE Transactions on Sonics and Ultrasonics in 1967"
502 citations
293 citations
TL;DR: In this paper, a stationary expression is derived from the equations of motion for short-circuit vibrations of fully-electroded piezoelectric ceramic discs with comparable diameter and thickness dimensions.
Abstract: The calculus of variations is applied to the analy- sis of the short-circuit resonant properties of piezoelectric vib- rators. A stationary expression is derived from the equations of motion for such vibrations. This stationary expression is used to develop a approximation technique for detennin- ing the short-circuit resonant frequencies and the corresponding mechanical displacements and electric potentials. The technique is used to analyze the short-circuit resonant properties of fully electroded piezoelectric ceramic discs with comparable diameter and thickness dimensions. Agreement of the barium titanate resonant frequency calculations with Shaw's published experimental frequency spectrum is better than three percent for the lowest eight resonances. Also, exact solutions have been obtained for the equivoluminal modes supported in isotropic elastic discs of certain diameter-to-thickness ratios. The application of the elastic portion of the present electroelastic approxi- mation to such discs produced frequency values for these modes which agree with the exact values to better than 0.3 percent. In the present paper, a stmatiormy expression describing the steady-state vihrations of n piezoelectric insulat,ing solid with N short-circuit,ed clectrodcs on its surface is derived from the steady-stale equations of motion. The stat'iorltlry property of this cspression is used to develop a variational approsirnation technjque for short-c-ircuit elec- troelastic vibration anxlyscs. The technique is applied to the short-circuit vibrations of fully-electroded piczoelec- tric ceramic discs mit.11 comparable diameter and thickness dimensions. Agreeenlent between the BaTi03 calculations and Slmv's cxpcrinlental data(61 proves to be considerably better than that obt,ained with past npproximntion tech- niques. (" The accuracy of the technique is investigated further by comparing calculations for isotropic elastic discs with some exact equivoluminal modes of such discs. C;\r,cur~cs OF Ii.i~~.\~~~~~ IS ELECTROELASTIC ~TI13R.4TIOXS
134 citations
TL;DR: In this article, the individual transducers or inactive layers of a sandwich structure affixed to an ultrasonic delay medium are described by the transformation matrix of their equivalent transmission line circuit.
Abstract: The individual transducer or inactive layers of a sandwich structure affixed to an ultrasonic delay medium are described by the transformation matrix of their equivalent transmission‐line circuit. The resulting simple expression and iterative procedures are well suited to digital computation. Computation reveals effects on input impedance, insertion loss, etc., of various arrangements of such layers, which may be qualitatively understood by visualizing separately the effects due to the mechanical‐resonance behavior of the whole stack and then due to the arrangement of piezoelectric material with respect to the stress distribution in various parts of the stack. Illustrative examples are presented for CdS and ceramic transducers.
118 citations
TL;DR: In this article, the elastic, piezoelectric, and dielectric constants of bismuth germanium oxide have been determined from dynamic measurements of thin plates of various orientations.
Abstract: Ahsiract-Room temperature values of the elastic, piezoelectric, and dielectric constants of bismuth germanium oxide have been determined. All of the elastic and piezoelectric constants were determined from dynamic measurements of piezoelectrically driven thin plates of various orientations. Specific combinations of electrode configurations and plate orientations yielding pure thickness-shear and thickness-extensional vibrations are considered. The usefulness of this material for ultrasonic device applications is discussed.
43 citations
23 citations
TL;DR: In this article, the design and performance of a 56-kHz ultrasonic atomizer are presented, and the effect of frequency and tip amplitude on the performance of at- omization is discussed.
Abstract: The design and performance of a 56-kHz ultrasonic atomizer are presented. The approach taken to achieve high ef- ficiency, reliability, and long transducer life is given; and the effect of frequency and tip amplitude on the performance of at- omization is discussed. Application of the atomizer to a reliable low rate oil burner and a unique drop formation experiment is described.
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TL;DR: In this paper, an investigation of ultrasonic attenuation in nickel, iron, and cobalt was carried out and the underlying mechanism of magnetic ultrasonic attenaution in the MHz range as a function of the temperature and the magnetic field intensity was investigated.
Abstract: Problems concerning the interaction of elastic and spin waves in ferromagnetics are presently being investigated thoroughly. Under certain circumstances, this interaction is very intense and the attenuation of elastic vibrations is very high. Satisfactory formulas exist for describing events in the kHz fre- quency range, but considerable deviations are manifested at higher frequencies. Moreover, the interpretation of the dependence of magnetic attenuation on the magnetic field intensity and on tem- perature requires that certain additional factors be accounted for. This paper describes an investigation of ultrasonic attenuation in nickel, iron, and cobalt, and attempts to explain the underlying mechanism of magnetic ultrasonic attenuation in the MHz range as a function of the temperature and the magnetic field intensity. Ultrasonic attenaution in nickel and iron was measured on single crystal specimens grown from 99.98 percent pure material. Ultra- sonic attenuation in cobalt was measured on polycrystalline speci- mens of the same purity. Attenuation was measured by the pulsed method with automatic recording of the attenuation as a function of the magnetic field intensity. Graphs of the results are included. Certain assumptions are postulated to explain the underlying dynamics.
TL;DR: In this article, ultrasonic energy applied to several metallurgical processes, exploring possible application to metal reinforcement was explored, and the authors explored possible application of metal reinforcement to metal.
Abstract: Ultrasonic energy applied to several metallurgical processes, exploring possible application to metal reinforcement
TL;DR: In this article, an equation describing ultrasonic attenuation at high temperatures in insulators can be obtained from the formalism developed for second viscosity in a simple manner, which is very easily generalized to include the complication of many types of modes (i.e., acoustic, optical, transverse, etc.), all of which have different thermal relaxation times as well as different Griineisen constants.
Abstract: An equation describing ultrasonic attenuation at high temperatures in insulators can be obtained from the formalism developed for second viscosity in a simple manner. The unreduced equation is very easily generalized to include the complication of many types of modes (i.e., acoustic, optical, transverse, etc.), all of which have different thermal relaxation times as well as different Griineisen constants. The analysis gives a prescription for the proper way to average over relaxation times and Griineisen con- stants.
Abstract: The parametric interaction between a continuous, forward-traveling longitudinal elastic wave pump and continuous, forward- and backward-traveling transverse elastic waves is considered. The coupling between the waves is provided by third-order terms in the elastic energy density. Using "typical" values for loss and nonlinearity and omitting all reflected waves in the analysis, the threshold value of longitudinal wave pump at 3 GHz needed to generate the two transverse waves from the thermal background is calculated. Also, amplification coefficients, for either forward- or backward-traveling transverse signal waves are calculated for a 3-GHz pump and for various pump amplitudes and interaction distances. It appears that amplification is only practical for a continous wave pump strain amplitude of at least 10-6 which with current experimental practice is probably too high to realize. If, however, continuous wave strain amplitudes this large could be realized, and if a reflectionless experimental situation could be achieved, the analysis will show that a high-gain, parametric transverse elastic wave amplifier could be constructed. The highgain region could be achieved by operating the device very near to the conditions where it becomes a "backward-wave-oscillator" (BWO).
TL;DR: In this article, a semigraphical approach to the solution of the trans-cendental resonance equation is developed along with a complete set of relations by which the performance and efficiency of the cavity design may be determined.
Abstract: Abstracf-The theoretical and practical aspects involved in the design of radial microwave cavities for ultrasonic applications are considered. A semigraphical approach to the solution of the trans- cendental resonance equation is developed along with a complete set of relations by which the performance and efficiency of the cavity design may be determined. Special application of this analysis is made in the design and construction of "S" band microwave ultra- sonic cavities for use in viscoelastic relaxation investigations in liquids at 3 GHz. N THE FIELD of microwave ultrmonics and laser communirations it is frequent,ly found t.hat radial microwave cavity resonat.ors provide a convenient, and efficient, means of exciting piezoelectric and electro- opt,ic materials. This paper is intended to present a treatment of the analysis and design considerations in- volved in the development of these radial cavities. The treatment developed here is presented primarily with a view towards the generation and detection of ultrasound for viscoelastic relaxat,ion studies;*') however, the basic cavit,y t,heory is quite general and should in principle be equally valid for elast.ooptic and electrooptic applications. The cavity adopted for analysis is of the symmet,ricttl double-reentrant configurative shown in Fig. 1. For the sake of clarity all tuning, coupling, and associated mech- anisms have been omitt,ed. A complete assembly drawing and description of the 3 GHz cavities construrted for viscoelastic studies is availahlc in the ljt,erat>ure. ('l Normally the material to be excited is placed in t,he gap region between the reentrant cavit.y electrodes. This material may be any of several low loss substances surh as ZnO, CdS, KDP, LiNboa, etc., depending on the :qplication. For the ultrnsonic application considered here the material was a single crystal disk of piezoelectric quartz, which was held in position by a teflon assembly as indicated in Fig. 1. The radial configuration was chosen for two basic reasons, t,hese being high filling factor and relative freedom from nonaxial elect,ric field components. These nonaxial fields can cause considerable trouble by generating un- wanted modes in t,he crystal. In order to provide flLsh over protect,ion under high pulsed power conditions and to insure that the excit.ed region was free of any edge mounting strains, the diameter
TL;DR: In this paper, an equation for the density operator with collisions was proposed for the propagation of ultrasonic waves in semiconductors and semimetals. And the results were compared with experiment.
Abstract: dispersion equation is calculated for the propagation of ultrasonic waves in semiconductors and semimetals. For investigations of this type of oscillation, knowledge of the complex longitude conductivity of medium is necessary. In the search of the complex conductivity of a medium in the Landau quantization conditions, an equation for the density operator is taken. It is shown that for the calculation of the longitudinal conductivity, the equation of density operator with collisions might be written as a “kinetic” equation for the separate density element. There is a possibility of oscillation of imaginary and real parts of conductivity. It is shown that imaginary parts of conductivity oscillate only under very strict conditions. Oscillations of the attenuation and velocity of sound connected with oscillations of real parts of conductivity are analyzed. The results are compared with experiment. Questions connected with the influence of “intervalley scattering” on amplitude of oscillation are discussed.