摘要:

Relations between the external sound field and the resulting radial vibration and strain of cylindrical vehicles are proposed and compared with measured data.

ISSN:0001-4966    

DOI:10.1121/1.1918148

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

This paper describes an improvement in the method of setting vibration amplitudes for calibrating vibration pickups by the disappearance of an interferometric fringe pattern. In the usual method, one plate of an interferometer is stationary, the other vibrates with the pickup, and the fringe pattern disappears at zeros of the Bessel functionJ0[(4πξ)/λ], where ξ is the amplitude of vibration and λ is the wavelength of light used. In the improved method, the fringes are observed by a photomultiplier, the previously stationary plate is vibrated at a modulating frequency much lower than the calibrating frequency applied to the pickup, and the signal from the photomultiplier, filtered at the modulating frequency, has minima at the zeros ofJ0[(4πξ/λ]. Observation of the nulls on a meter allows faster calibration with greater precision and less observer fatigue.

ISSN:0001-4966    

DOI:10.1121/1.1918149

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

An analytical method is presented for determining the natural frequencies for the axisymmetric vibrations of a truncated, circular, conical shell supporting a mass fastened to its small end.

ISSN:0001-4966    

DOI:10.1121/1.1918150

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

In order to evaluate the performance of shock mountings in a simple manner, it is very desirable to express by a single quantity the liability to damage of the contents of fragile equipment. The conditions on shock duration under which the acceleration, displacement, or velocity associated with the input transient may be employed to describe the liability to damage in place of the full shock spectrum are therefore discussed.In shock‐mounted equipment it often appears desirable to avoid mechanical elements that, by virtue of their low resonant frequencies, are sensitive to changes in displacement or velocity. If this is possible, acceleration remains as the factor of chief concern, and a mount must be chosen to provide an acceptable compromise between the resulting reduction in acceleration and the introduction of relative motion. Characteristic curves facilitating this choice are proposed, and the influence of mount nonlinearity and damping on the curves is briefly discussed.

ISSN:0001-4966    

DOI:10.1121/1.1918151

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

For some experimental setups involving a cantilever beam in steady‐state vibration there exist simple relations between the tip‐to‐root displacement‐amplitude ratio and the damping of the beam. Derivations of these relations are presented along with a statement of conditions for their legitimate application.

ISSN:0001-4966    

DOI:10.1121/1.1918152

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

The correlation properties of dispersively propagating flexural waves traveling on long thin bars have been studied experimentally. The cases of a traveling wave with no reflections, with one reflection, and with many reflections have been investigated. It is shown that dispersion considerably complicates the interpretation of the cross‐correlation function. The nature of the complications and the extent to which progress has been made in the interpretation of results is described.

ISSN:0001-4966    

DOI:10.1121/1.1918153

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

Obtaining adequate speech privacy in modern buildings is one of the important goals of the architect and consultant. This paper deals with the development of a rating method which takes into account the several factors influencing speech privacy. Our work in this area began with a brief laboratory study. The results indicated that speech privacy is related to speechintelligibilityrather than tolevel. The initial experiments were supplemented with an analysis of about 40 case histories representing about 400 pairs of spaces in different kinds of buildings. There appears to be good correlation between the articulation index of intruding speech sound and the reactions of building occupants.

ISSN:0001-4966    

DOI:10.1121/1.1918154

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

A survey is made of past and present systems for rating the sound‐insulation value of building walls and floors. It is observed that in most countries ratings based on “average” transmission losses have been replaced by systems that compare transmission‐loss characteristics with a standard contour. An example of this approach is the new sound‐transmission class contained in ASTM E90‐61T. This is discussed from various theoretical and practical viewpoints, and it is concluded that the sound‐transmission class is a useful rating system for common architectural problems.

ISSN:0001-4966    

DOI:10.1121/1.1918155

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

The acoustic impedance and absorption characteristics were investigated for open‐celled urethane foams with and without surface coatings. The variables considered were the foam thickness, cell size and density, and the coating material mass and thickness. The application of thin films of area density in the order of 0.005 g/cm2to the foams resulted in an increase in the absorption for the foams of12and 1 in. thickness with variable results for foams of 2 in. thickness. The addition of coatings of density in the order of 0.05 to 0.45 g/cm2increased the absorption at a frequency of 240 cps but otherwise decreased the absorption. The results were essentially independent of the nature of the surface coating and, within limits, depended largely on the surface mass per unit area. Also noted was an absorption increase which was attributed to the vibrating of the surface material in one of its natural modes.

ISSN:0001-4966    

DOI:10.1121/1.1918156

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP

摘要:

Subjects were asked to change the level of a short noise burst in order to make it equally as loud as a standard 500‐msec burst. Above some critical duration loudness is independent of duration but below it for each decade decrease in duration the level of the short burst must be increased about 12.5 db, independent of the level at which the standard burst is presented.

ISSN:0001-4966    

DOI:10.1121/1.1918157

出版商:Acoustical Society of America    

年代:1962

数据来源: AIP