ISSN:0001-4966    

DOI:10.1121/1.1915949

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915950

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915951

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

When a mechanical system is undergoing vibrations whose amplitudes are small but not infinitely small, then the Lagrangian equations of motion are of a nonlinear character and the phenomenon is most complex. The Laplacian transform, or operational treatment of linear dynamical systems is being more and more widely employed in the treatment of linear systems leading to a set of ordinary differential equations or to partial differential equations of the linear type. The use of the operational method in nonlinear cases here presented appears to be new. For purposes of illustration, a system of acoustical interest will be considered although the method is general and yields interesting results in a wide variety of cases.

ISSN:0001-4966    

DOI:10.1121/1.1915952

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915953

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

Calculation is made of the transmission of harmonic compressional waves through a finite solid filter structure consisting of a metal rod loaded at equal intervals with heavy metal collars. The theory is then tested experimentally for the special case where the finite structure (consisting of 6 sections) is terminated by a finite rod with a free end. The structure acts as a low pass filter with a cut‐off at about 2000 cycles and no further transmission up to 12,650 cycles. The transmission in the transmission band shows a series of peaks whose positions, with one exception, are accurately verified experimentally.

ISSN:0001-4966    

DOI:10.1121/1.1915954

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915955

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

The use of the Rayleigh disk for measurement of extremely great sound intensities is discussed, and it is stated that the Rayleigh disk method is applicable also in this case. The Rayleigh disk may even be used in the open air as part of a pointer instrument when properly shielded, thus giving a means of directly measuring the actual sound intensity (in watts/cm2) of intense sound fields. The measurement also involves a determination of the direction of propagation of energy. The calculation of the total flux over the opening of a sound sender, giving the actual acoustical output in watts, is in that way very much simplified. As a secondary instrument a crystal microphone, calibrated by comparison with the Rayleigh disk instrument, was used. When used in extreme sound fields it was directly connected with a rectifier galvanometer. Reports are given of measurements of the total output of a membrane sender and of that of a diaphone. In the first case measurements were also made of the different kinds of losses occurring both in the electrical and the acoustical oscillation circuit, while the vibration losses were determined from the power balance and vibration measurements. Oscillograms of sound wave form are given and discussed.

ISSN:0001-4966    

DOI:10.1121/1.1915956

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1915957

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP

摘要:

The mathematical theory of vibrating membranes or plates, which is usually applied to squares and rectangles, may also be used for triangles provided the equations are plotted on axes which are not rectangular. These triangles are then fitted together to produce many sided symmetrical plates. Thus the Chladni patterns are found mathematically for polygonal membranes or plates. If one angle of the triangle is made very small, the plates are practically circular so that these equations also give the patterns on circular plates (approximately) for special cases. The triode valve oscillator which drives the plates is calibrated accurately so that the frequency of the plates is found at the time the patterns are formed. A table gives a comparison between the observed and calculated frequencies.

ISSN:0001-4966    

DOI:10.1121/1.1915958

出版商:Acoustical Society of America    

年代:1938

数据来源: AIP