scholarly journals Indonesian Wood as Material for Acoustic Guitars and Violins

2017 ◽  
Vol 3 (1) ◽  
pp. 11-17
Author(s):  
Indraswari Kusumaningtyas ◽  
Subagio Subagio
Keyword(s):  
Frequency Spectrum ◽  
Vibration Frequency ◽  
Sound Radiation ◽  
Damping Factor ◽  
Suitable Alternative ◽  
Acoustical Properties ◽  
Local Material ◽  
Radiation Coefficient ◽  
Back Plate ◽  
Vibration Frequency Spectrum

Traditionally, acoustic guitars and violins are made from European woods. Spruce is most preferred for the top plate (soundboard), whereas maple, sycamore and rosewood are often used for the back plate. However, these woods are not easily available in Indonesia. In this paper, we present a study on the suitability of a selection of Indonesian woods, namely acacia, mahogany, pine, sengon and sonokembang, as materials for acoustic guitars and violins. The most important acoustical properties for selecting materials for musical instruments, i.e. the speed of sound, the sound radiation coefficient and the damping factor, were investigated. Furthermore, the performance of pine and mahogany were tested by making them into a violin and a guitar. The vibration frequency spectrum and the damping factor of the top plate were measured. The results show that the acoustical characteristics of mahogany are very close to those of maple and still quite close to those of Indian rosewood, which makes it a very suitable local material for back plates. Pine has quite similar acoustical characteristics to spruce. Although its sound radiation coefficient is slightly lower, its aesthetic appeal and workability makes pine a suitable alternative for top plates. However, instruments with pine top plates exhibit different tonal colour compared to instruments with spruce top plates, due to some differences in the vibration frequency spectrum. Furthermore, the generally higher damping factors of pine and mahogany compared to those of the European woods should be taken into account, because they affect the sustain-time of the generated sound.

A Method of Measurement and Monitoring to the Train's Vibration Frequency Spectrum-Varying Fault

2010 ◽  
Vol 36 ◽  
pp. 96-102 ◽  
Author(s):  
Jing Wang ◽  
Te Fang Chen ◽  
Cai Lun Huang ◽  
Qian Cheng Zhao
Keyword(s):  
Frequency Spectrum ◽  
Vibration Frequency ◽  
Sampling Method ◽  
Vibration Signal ◽  
Periodic Signal ◽  
Signal Acquisition ◽  
Speed Fluctuation ◽  
Spectral Analysis Method ◽  
Spectral Smearing ◽  
Vibration Frequency Spectrum

In condition monitoring of train, because of load change, speed fluctuation and other effect factors, it may cause vibration frequency spectrum migration. If using the common vibration signal acquisition and spectral analysis method to this fault, there will be a result of characteristic spectral smearing, which will lead to misdiagnosis or missed diagnosis. To solve this problem, the vibration mechanism of spectrum-varying fault was discussed. This paper studies a pulse-triggered sampling method of integral periodic signal, the equal angle re-sampling method and other appropriate signal processing method. The feasibility and validity of this method and technology has been verified by the application in Liuzhou Railway Bureau .

Vibration Analysis of Vehicle-Rail System under the Condition of Track Stiffness Irregularity

2013 ◽  
Vol 368-370 ◽  
pp. 1431-1437 ◽  
Author(s):  
Tian Yu Lu ◽  
Zu Jun Yu ◽  
Hong Mei Shi
Keyword(s):  
Frequency Spectrum ◽  
Vibration Frequency ◽  
Vibration Analysis ◽  
High Speed ◽  
Track Structure ◽  
High Speed Train ◽  
Track Maintenance ◽  
Rail System ◽  
Coupling System ◽  
Track Stiffness

The interaction of track structure and high-speed train has greater impact on safe and steady running of the trains. This paper obtained acceleration and frequency spectrum of the train's running vibration in the case of sleeper’s spacing and continuous failure， and continuous and spacing loose tie by establishing the vertical model of vehicle-track coupling system, and analyzed the sleeper failure and loose tie which has a greater impact on the 40-80 Hz vibration frequency of the train, which provided a basis for track maintenance.

Large-amplitude vibration of imperfect angle-ply laminated rectangular plate with viscous damping

2015 ◽  
Vol 12 (3) ◽  
pp. 207-214 ◽  
Author(s):  
He Huang ◽  
David Hui
Keyword(s):  
Boundary Conditions ◽  
Vibration Frequency ◽  
Large Amplitude ◽  
Plane Boundary ◽  
Damping Factor ◽  
Viscous Damping ◽  
Damped System ◽  
Amplitude Vibration ◽  
Out Of Plane ◽  
Large Amplitude Vibration

This paper solves the modified-Duffing ordinary differential equation for large-amplitude vibration of imperfect angle-ply rectangular composite plate. Viscous damping is then introduced in the derivation and analyzed under four different boundary conditions (combining two out-of-plane boundary conditions with two in-plane boundary conditions). It has been shown that even a small viscous damping factor, for example 0.1 from an ordinary damped system can largely decrease the vibration amplitude within several periods. Yet at the same time, the vibration frequency only changes slightly. Furthermore, viscous damping is proved to significantly affect the vibration frequency and the vibration mode from nonlinear to much more linear. This effect is irrelevant to boundary conditions and geometric imperfections.

Isospectral Euler-Bernoulli beams with continuous density and rigidity functions

1987 ◽  
Vol 413 (1844) ◽  
pp. 235-250 ◽  
Keyword(s):  
Boundary Condition ◽  
Free Vibration ◽  
Exact Solutions ◽  
Vibration Frequency ◽  
Flexural Rigidity ◽  
Homogeneous Case ◽  
Continuous Density ◽  
Free Vibration Frequency ◽  
End Conditions ◽  
Vibration Frequency Spectrum

Isospectral systems are those that have exactly the same free-vibration frequency spectrum with respect to a given boundary condition configuration. In this paper, seven different classes of inhomogeneous Euler-Bernoulli beams with continuous density and flexural rigidity functions are found that are analytically solvable and that are isospectral with a homogeneous beam in the clamped-clamped configuration. Of these exact solutions, one class is isospectral with the homogeneous case in all ten distinct configurations obtainable from clamped, sliding and two antiresonant end conditions, whereas another class is isospectral in the six configurations with clamped, hinged or free end conditions. A connection with inverse problems is discussed.

Mechanical-Condition Assessment of Power Transformer Using Vibroacoustic Analysis

2012 ◽  
Vol 500 ◽  
pp. 40-44 ◽  
Author(s):  
Eugeniusz Kornatowski
Keyword(s):  
Steady State ◽  
Vibration Frequency ◽  
Power Transformer ◽  
Wide Frequency Range ◽  
Analysis Method ◽  
Frequency Range ◽  
Harmonic Frequency ◽  
Measurement Results ◽  
Relative Coefficient ◽  
Vibration Frequency Spectrum

This paper presents a method for vibroacoustic analysis of a transformer in the steady state. The standard approach to this problem has been based on analysis of the vibration frequency spectrum recorded with an accelerometer mounted on the transformer’s tank. To improve legibility of measurement results, the paper suggests the analysis method for the relative coefficient of harmonic frequency contents hnorm(f). The conducted experiment showed that high values of hnorm within a wide frequency range testify to deformation of windings and degradation of solid insulation.

Vibration Frequency Spectrum Measurement on a Hydraulic Turbine Runner Chamber for a Large Bulb Hydraulic Generator Set

2014 ◽  
Vol 889-890 ◽  
pp. 712-717
Author(s):  
Chang Zheng Huang ◽  
Jin Li ◽  
Zu Chao Yang
Keyword(s):  
Frequency Spectrum ◽  
Optimization Design ◽  
Hydraulic Turbine ◽  
Spectrum Measurement ◽  
Measurement And Analysis ◽  
Turbine Runner ◽  
Analysis System ◽  
A Charge ◽  
Hydraulic Generator ◽  
Vibration Frequency Spectrum

The vibration is severe for a hydraulic turbine runner chamber of a large bulb hydraulic generator set. A measurement and analysis system is composed of an acceleration transducer, a charge amplifier, and a dynamic data collecting & analyzing system. It is used to test the frequency spectrum, which provide a basis for the optimization design based on the modal analysis, so that its natural frequencies can stagger these frequencies of vibration sources, the resonance does not occur and the vibration is reduced.

Modelling noise radiation from concrete box girder bridges as an infinitely long periodic structure excited by a high-speed train

2021 ◽  
pp. 1-33
Author(s):  
Yuanpeng He ◽  
Gong Cheng ◽  
Jian Han ◽  
Xiaozhen Sheng
Keyword(s):  
Vibration Frequency ◽  
High Speed ◽  
Sound Radiation ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Frequency Spectra ◽  
Box Girder ◽  
Noise Radiation ◽  
Girder Bridges ◽  
Concrete Box Girder Bridges

Abstract Concrete box girder bridges occupy over 80% of the total mileage of the Chinese high-speed railway. The box girder structure has many natural modes of low frequencies, which can be excited by a train passing at high speed, generating low-frequency bridge noise. This paper is concerned with the prediction of such bridge noise and reports a prediction model. The model, as other existing models of the same nature, also incorporates two parts, one dealing with vehicle-track-viaduct dynamics and the other dealing with sound radiation from the girders, but takes into account more features related to high speed. In this model, vehicle-track-viaduct dynamics is dealt with in the frequency-domain based on the theory of infinitely long periodic structure and the Fourier-series method, predicting vibration frequency spectra for each and every box girder. The predicted vibration frequency spectra of all the box girders are expressed as a sum of propagating waves at different wavenumbers, and sound radiation from each propagating wave is evaluated using the 2.5D acoustic boundary element method. This approach to sound radiation enables contributions from all the box girders to be included at a reasonable computational cost. The paper continues with a comparison in bridge vibration and noise between prediction and measurement for a typical site. And finally, based on the parameters of that site, characteristics of noise radiation from the concrete box girders are studied using the prediction model.

Discussion on the Sound Radiation Coefficient of Building Materials

2012 ◽  
Vol 446-449 ◽  
pp. 1325-1328
Author(s):  
Yan Yang ◽  
Xian Feng Huang ◽  
Jun Liu
Keyword(s):  
Building Materials ◽  
Sound Radiation ◽  
Radiation Coefficient
Sign in / Sign up

Export Citation Format

Share Document