The first part of this paper deals with the finite element simulation of a slant cantilever beam, and the second part contains an approximate equation formula of its resonance frequency. We investigated such vibrational behaviors of a slant cantilever beam because we had to design a large-diameter torsional vibrator with many slant slits cut into its end-face for a rod-type ultrasonic motor. Also, we thought that the simulated and investigated results on the slant cantilever beam might be very useful in other applications, for example, vibrational sensors. In this paper, therefore, we present some finite element simulations of aslant cantilever beam and we investigate the results of its approximate equation formula, as academic research material.

抄録全体を表示

The timbre of compound tones consisting of four amplitude modulated waves is examined by psychoacoustical experiments using a similarity judgement of timbre. The obtained data are analyzed by a multi-dimensional scaling (MDS) method. The MDS solutions are different according to the frequency regions of the AM waves. When the frequency region is low and there is one AM wave within the bandwidth of the auditory filter, envelope correlations between AM waves are a determinant factor of timbre. However, the three dimensional MDS solution suggests that all the envelopes do not affect the timbre in the same manner. The effect of the lowest AM wave is not clear. As the frequency region is higher, the effect of the envelope correlation is less dominant. The effect of thedepth of amplitude modulation of the compound waves then becomes dominant. When there are two AM waves within the bandwidth of the auditory filter, we no longer see the effect of the envelope correlation between AM waves. In this case, the correspondence of the shape of the compound envelopes of two AM waves affect the timbre.

抄録全体を表示

This paper describes new cuts.for torsional mode quartz crystal resonators, which are called “TT (Y)-cut.” The object of this paper is to propose new cuts for torsional quartz crystal resonators with a zero temperature coefficient and to clarify frequency constant, frequency temperature behavior and electrical equivalent circuit parameters for the typical cuts. First, we show a frequency equation that is given as a function of torsional rigidity C_t. Namely, the problem of a vibration for torsional mode is substantially equivalent to that of torsional rigidity C_t, and it is obtained from stress function Ψ which satisfies the boundary conditions. Next, from the frequency equation numerous relationships where α reaches zero are found to exist between thickness-to-width ratio R_zy and cut angle (φ, θ), especially, the second order temperature coefficient β has a small value of -1.25×10^-8/°C² whose absolute value is approximately one third of the flexural mode quartz crystal resonators. The value of β is then compared with the measured data of -1.00×10^-8/°C². Finally, it is shown that torsional quartz crystal resonators of tuning fork-type are successfully obtained with a small R₁ of 3.0 to 6.5 kΩ and a large Q value of 175, 000 to 347, 000 in a frequency range of about 300 to 600 kHz.

抄録全体を表示

Elastic constants of unidirectional carbon fiber reinforced polymer (CFRP) laminates are determined by water immersion ultrasonic sing-around method. The unidirectional CFRP has hexagonal symmetry, and the five independent stiffness constants (C₁₁, C₁₂, C₁₃, C₃₃, C₄₄) are derived from the two series of sing-around periods. In the one series, the fiber direction is set to be always perpendicular to the incidence-refraction plane. From the measurement result, C₁₁, C₁₂ and C₆₆ are obtained explicitly. In the other series, the fiber direction is set to be contained in the incidence-refraction plane. From this result, C₁₃, C₃₃ and C₄₄ are obtained by successive approximation using least square method.

抄録全体を表示

The property of the fundamental and second harmonic components of the acoustic pressure in the beam emitted from a uniformly excited focusing source, which is detected by a concave receiver put normal to the acoustic axis beyond the focal region, has been investigated for both the cases of the free field and the field with inserted sample. Calculation based on the successive approximation solution for the Khokhlov-Zabolotskaya-Kuznetsov equation is validated through experiments. It has been clarified that the range dependence of the fundamental component amplitude differs from that of the second harmonic, unlike the case of a Gaussian source, and the cancellation of the second harmonic components generated in front of and beyond the focal region is degraded comparing with the case of Gaussian source. The signal experimentally received beyond the sample corresponds fairly well with the theoretical prediction, taking into account the acoustic properties of the inserted sample. However, the result of experimental determination of the B/A utilizing such responses shows slightly poorer agreement with the literature values, due to the less sensitive property of the second harmonic component to the inserted sample.

抄録全体を表示

A new method is proposed for acoustical measurement and analysis of anti-resonance characteristics of the vocal tract. This method evaluates details of vocal tract transfer function by measuring input and output pressures for a series of vocal tract segments from a selected point within the tract to the radiation end. Theoretical and experimental studies were conducted on acoustic tubes of known geometry in order to assess the accuracy of this method. Experimental results of the acoustic tubes were in agreement with their numerical values with about 2% error for the anti-resonance frequencies, and 4% error for the resonance frequencies. This method was proven to be capable of detecting the location of antiresonators. In this study, sweeptone signal and glottal sound source were employed as the excitation sources. The two types of excitation sources showed no significant difference in the resonance and anti-resonance frequencies. It is suggested that the method is applicable for detail estimation of vocal tract transmission characteristics from short-period data of natural utterances.

抄録全体を表示